JCB JS Machines Track Service Manual 9803/3010-4 – PDF DOWNLOAD

Track Service Manual JS Machines Section 1 - Contents Section 2 - Introduction Section 3 - Links Section 4 - Sprockets Section 5 - Track Pins and Bushes Section 6 - Shoes Section 7 - Idlers Section 8 - Carrier Rollers Section 9 - Track Rollers Section 10 - Guards Section 11 - Service Information

Publication No.

9803/3010-4

World Class Customer Support Copyright © 2004 JCB SERVICE. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any other means, electronic, mechanical, photocopying or otherwise, without prior permission from JCB SERVICE. Issued by JCB Technical Publications, JCB Aftermarket Training, Woodseat, Rocester, Staffordshire, ST14 5BW, England. Tel +44 1889 591300 Fax +44 1889 591400

Section 0 - Track Service Manual

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Section 1 - Contents Contents

Contents Page No. Introduction System Life and Components Wear .........................................................2 - 1 Ground Characterisitics .......................................................................2 - 1 Enviroment ..........................................................................................2 - 1 Terrain .................................................................................................2 - 2 Application Effects ...............................................................................2 - 3 Wear Rate Variables ............................................................................2 - 3 Checking and Adjusting Track Tension ....................................................2 - 4 Links Link Rail Wear ..........................................................................................3 - 7 Measurement Techniques ...................................................................3 - 7 Wear Limits - Service and Destruction ................................................3 - 7 Wear Charts ........................................................................................3 - 7 Rebuildability .......................................................................................3 - 7 Link Wear Patterns ...................................................................................3 - 9 Rail (Top) Wear ...................................................................................3 - 9 Uneven Scalloping Wear on Rail Top ..................................................3 - 9 Rail Side Wear ..................................................................................3 - 10 Rail Inside Gouged ............................................................................3 - 10 Pin Boss Top Worn ............................................................................3 - 10 Elongation of Counterbore ................................................................ 3 - 11 Depth Wear in Counterbore .............................................................. 3 - 11 Face Wear .........................................................................................3 - 12 Pin Boss End - Guiding Guard Wear .................................................3 - 12 Link Structural Problems ........................................................................3 - 13 Rail Chipping or Flaking ....................................................................3 - 13 Link Cracking .....................................................................................3 - 13 Pin & Bush Bore Enlargement ...........................................................3 - 14 Track Pins & Bushes Track Bush Wear ....................................................................................4 - 15 Measurement Technique ...................................................................4 - 15 How to Interpret Wear on Track Bushes .................................................4 - 18 External Wear - Assembled or Disassembled Track .........................4 - 18 Other Wear Patterns-Disassembled Track End Wear .......................4 - 19 Structural Problems on Bushes .........................................................4 - 20 Track Pitch Internal Wear .......................................................................4 - 22 Measurement Technique ...................................................................4 - 22 Wear Limits to Service and Destruction and Percent Worn Chart .....4 - 23 Wear and Structural Problems on Track Pins .........................................4 - 24 Pin O.D. (External) Wear [and Bush I.D. (Internal) Wear] .................4 - 24 Pin End Wear ....................................................................................4 - 24 Pin Loosening ....................................................................................4 - 25 Pin Breakage .....................................................................................4 - 25 Shoes Shoe Structural Problems .......................................................................5 - 27 Shoe Bending, Cracking and Breaking .............................................5 - 27 Bolt Hole Opening Out (With loose hardware) ..................................5 - 27 Idlers Idler Tread wear .....................................................................................6 - 29 Measurement Technique ...................................................................6 - 29 Wear Limits - Service and Destruction ..............................................6 - 29

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Section 1 - Contents Contents

Contents Page No. Idler Wear Patterns .................................................................................6 - 30 Tread Wear - Normal wear pattern ....................................................6 - 30 Flange Side Wear ..............................................................................6 - 30 Flange Top Wear (may be domed) ....................................................6 - 31 Carrier Rollers Carrier Roller Tread Wear ......................................................................7 - 33 Measurement Technique ...................................................................7 - 33 Wear Limits - Service or Destruction .................................................7 - 33 Wear Charts ......................................................................................7 - 33 Rebuildability .....................................................................................7 - 33 Carrier Roller Wear Patterns ..................................................................7 - 34 Tread Wear (Uniform) ........................................................................7 - 34 Uneven Flange Side Wear and Offcentre Tread Wear ......................7 - 34 Flat Spots on Tread ...........................................................................7 - 35 Track Rollers Roller Tread Wear ..................................................................................8 - 37 Tread Measurement Technique .........................................................8 - 37 Roller Wear Patterns ..............................................................................8 - 39 Tread Wear (Normal wear pattern) ....................................................8 - 39 Flange Side Wear (Inner and/or outer sides facing tread) ................8 - 40 Flange Top Wear ...............................................................................8 - 40 Sprockets Sprocket Wear ........................................................................................9 - 41 Sprocket Wear Patterns ..........................................................................9 - 42 Root Wear .........................................................................................9 - 42 Reverse and/or Forward Drive Side Wear ........................................9 - 43 Reverse Drive Side Tip Wear ............................................................9 - 43 Forward Drive Side Tip Wear ............................................................9 - 44 Sprocket Side Wear and Corner Wear or Gouging ...........................9 - 44 Guards Guiding Guard Wear .............................................................................10 - 45 Need For Roller Guards .......................................................................10 - 46 Conditions For Considered Use Of Roller Guards ...............................10 - 47 Service information Bush Wear Guide (Ital Track) ............................................................... 11 - 49 Bush Wear Guide (Berco Track) ........................................................... 11 - 50 Pin & Bush Wear Guide (Ital Track) ...................................................... 11 - 51 Pin & Bush Wear Guide (Berco Track) ................................................. 11 - 52 Track Link Rail Wear Guide (Ital Track) ................................................ 11 - 53 Track Link Wear Guide (Berco Track) .................................................. 11 - 54 Upper Roller Wear Guide (Ital Track) ................................................... 11 - 55 Upper Roller Wear Guide (Berco Track) ............................................... 11 - 56 Lower Roller Wear Guide (Ital Track) ................................................... 11 - 57 Lower Roller Wear Guide (Berco Track) ............................................... 11 - 58 Idler Roller Wear Guide (Ital Track) ...................................................... 11 - 59 Idler Roller Wear Guide (Berco Track) ................................................. 11 - 60 Track Plate Wear Guide (Ital Track) ..................................................... 11 - 61 Track Plate Wear Guide (Berco Track) ................................................. 11 - 62

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Section 2 - Introduction Introduction System Life and Components Wear

Introduction System Life and Components Wear Life and wear are generally related characteristics and the enviroment.

to

ground

Enviroment Materials & Chemicals

Ground Characterisitics Abrasiveness Rating – High abrasiveness rated grounds include wet soils containing high amounts of hard and sharp sand particles.

– Moderate abrasiveness rated grounds include slightly damp soils that contain a low portion of rounded sand particles or rock fragments – Low abrasiveness rated grounds include dry silt and clay soils without any content of rocks and sands

impact

– Natural and man-made corrosives such as salts and sulphurs, acids, and organic chemicals can eat away or crack hardened wear/contacting surfaces.

Additionally, chemicals can cause swelling and failure of roller and idler O-rings within the sealing groups.

Temperature – Temperature of both environment and materials could have detrimental effect on undercarriage components: a very high temp can soften hardened steel; a very low temp can increase steel brittleness and decrease oil lubrication.

– impact can be described as the amount of grouser penetration in the ground.

– The effect can be reduced by decreasing machine speed and by using the smallest track shoes possible.

– The weight of the machine is also a determining parameter, even if it can not be modified.

Packing – Packing materials are any material that stick to or pack around moving components.

– Packing materials can be classified as extrudable and non-extrudable.

Major effects: – Incorrect engagement between the components causing tightening of the track chain, high loads on the undercarriage components, interference and dramatically increases the wear rate.

– Abnormal increase of the wear effect due to abrasive particles incorporated in the packed material.

– Moderate amounts of moisture contribute to packing.

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Section 2 - Introduction Introduction System Life and Components Wear

Terrain

Side-hill

Terrain structure might shift the machine center of gravity increasing the loads on individual undercarriage components.

Up-hill

– Increased wear of the rail sides, roller and idler flanges, bushing ends and track shoe ends.

On a Crown

Fig 1.

– Increased wear rate on rear rollers and increasing forward drive wear of sprocket and bushing.

Down-hill

Fig 3.

– High wear of front rollers; reduced rate of sprocket and bushing wear.

In a Depression Fig 2.

– Higher wear rate of front rollers; reduced rate of sprocket and bushing wear.

Fig 4.

– Higher wear on rear rollers and increasing forward drive wear of sprocket and bushing.

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Section 2 - Introduction Introduction System Life and Components Wear

Application Effects

Reverse Operation

Dozing – Shifts machine weight forward causing faster wear on the front rollers and idler than on the rear rollers.

Drilling

– Causes higher wear rates on bushings and sprockets than forward operation. Since reverse travel is also equivalent to unproductive use of the machine, unnecessary reverse operations are notrecommended.

Track Tension

– Shifting the weight from one side to the other can increase the wear of the outer components.

– Incorrect track tension will result in faster wear of undercarriage components.

Wear Rate Variables

– An over tightened track chain could reduce the wear life of bushing and sprocket by 2.5 – 3 times.

Speed

– This situation also reduces productivity and increases fuel consumption.

– Wear rate is directly related to speed and distance travelled, not just hours worked.

Turning – Wear rate increase with increased turning. Turning results in higher interference loads between moving components, especially on roller and idler flanges.

Counter-Rotation – Consists in causing one track to travel forward while the other travels in reverse. The load applied to the side of undercarriage components increases the wear rate.

Spinning Track – Spinning the tracks increases the wear rate on all components without accomplishing any useful work.

Track shoes are particularly affected.

Counter-Rotation – Consists in causing one track to travel forward while the other travels in reverse. The load applied to the side of undercarriage components increases the wear rate.

Favored Side Operation

Track Shoes – Shoes have to guarantee good traction and flotation.

They have to allow the grouser to penetrate into the ground without letting the track shoes sink below the surface.

– Shoes wider than necessary are detrimental to all undercarriage components since they are generating uneven forces that are affecting the complete system.

Track Alignment – Proper alignment of undercarriage components is a must to avoid accelerated and unbalanced wear.

– Each discrepancy in the roller frame, idler and sprocket will be detrimental to roller treads and flanges, link rails and sides of the sprocket/segments and the idler center flange.

Cleanliness and Parking – Cleaning the undercarriage as soon as possible helps to avoid packing effect and removes abrasives and chemicals responsible for shortening wear life.

– Machine should always be parked on a flat surface in order to avoid static loads applied for a long time on one side only. This will avoid plastic deformation of sealing groups.

– Uneven wear rate between the two sides of the undercarriage will result if work is always performed with a greater load on one side.

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Section 2 - Introduction Introduction Checking and Adjusting Track Tension

Checking and Adjusting Track Tension It is important to regularly check and adjust track tension, poor tensioning can reduce track chain life by up to 50%.

Always check the track tension when checking the track wear check.

1

Prepare the Machine.

A

Position the machine on level ground. Run it backwards and forwards several times. Stop after running it forwards.

Fig 5.

Carry out steps 1 to 3 of Cleaning the Tracks (in the operators Handbook). Block up the undercarriage frame. Finish track rotation by running the track forwards. Stop the engine and remove the starter key.

Check the Tension - JS330 - JS460 Measure gap 5-A in line with the third roller (JS330/ JS460) from the front and between the lower surface of the track frame and the upper surface of the shoe.

The dimension should be 340-360 mm for hard ground conditions.

!MWARNING Raised Machine NEVER position yourself or any part of your body under a raised machine which is not properly supported. If the machine moves unexpectedly you could become trapped and suffer serious injury or be killed.

3

INT-3-3-7_1

2

Check the Tension - JS130 - JS260 Measure gap 5-A in line with the third roller (JS130/ JS160) or fourth roller (JS200/JS260) from the front and between the lower surface of the track frame and the upper surface of the shoe. The dimension should be 275-295 mm for hard ground conditions. For operation on soft sand or sticky mud it should be 320340mm.

Adjust the Track Tension Adjustment is made by either injecting or releasing grease from the check valve 6-B. Inject grease to reduce the gap (increase the tension) or open to release grease and increase the gap.

If a gap 6-C exists between the idler wheel shaft and the track frame, you may use pressure to apply the grease.If there is no gap 6-C after the application of grease, then the necessary repairs must be carried out.

C

B

Fig 6.

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Section 2 - Introduction Introduction Checking and Adjusting Track Tension

!MWARNING When opening the check valve always stand to one side and loosen a little at a time until grease starts to come out. If you over-loosen too much grease could spurt out or the valve cover fly out and cause serious injury.

8-3-4-5

!MWARNING Under no circumstances must the check valve be dismantled or any attempt made to remove the grease nipple from the check valve.

8-3-4-9

Note: Excessive tension can cause the track rail to wear the drive rollers and sprocket, insufficient tension can cause wear to the drive sprocket and track rail.

4

Lower the Track Remove the blocks from beneath the undercarriage and lower the track to the ground using the boom and dipper controls.

5

Repeat for the Opposite Track Slew the boom round to the other side and repeat steps 1 to 4 above.

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Section 2 - Introduction Introduction Checking and Adjusting Track Tension

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Section 3 - Links Links Link Rail Wear

Links Link Rail Wear Measurement Techniques The only measurable wear position on the link is rail (top) wear. It is measured with a broad base depth gauge from the rail surface to the track shoe plate. This dimension is the rail height. The correct location for track link measurement is outside of the links at the end of the track pin. Position the depth gauge as close to the end of the pin as possible, making sure links and shoe surface are clean.

Ensure the gauge is flat against the link rails and perpendicular to the shoe surface. Measurement should be made to the closest 0.25 mm (0.01 in).

rebuildability. If the link is worn to approximately 120%, structural damage will result in the form of cracking, breaking and pin and bush loosening.

Wear Charts Wear charts for links have a built in factor allowing for faster wear rate as the hardness of the steel decreases below the case hardened depth. This is true for all components where the allowable wear is greater than the case hardened depth. In links the rate is about three times as fast after the case hardened depth is worn away.

Rebuildability The size of components used on JCB machines (in common with other excavators) means that rebuilding is not usually economically feasible. Track links, however, can usually be successfully rebuilt with submerged and/or automatic welding to replace the worn away rail (top) surface provided the link meets the following criteria:

Fig 1.

1

Rail wear at a point above the pin boss is not less than 80% or more than 100%.

2

Unevenness of rail height is not excessive.

3

Rail side wear due to roller flange or guiding guards or inside rail gouging by the sprocket hasn't reduced rail width significantly.

4

Pin boss is not worn due to roller flange or guiding guards causing reduced pin retention.

5

Counterbore depth and elongation wear (with Sealed Track) will not significantly affect resealing of the pins and bushes.

6

Face wear (area surrounding the link, bush and counterbores) has not reduced the thickness of the rail in that area by more than 20%.

7

Rail chipping or flaking hasn't caused more than 30% of the rail surface to be removed.

Wear Limits - Service and Destruction Link wear limits have been determined by setting the allowable wear equal to a fraction of the pin boss to roller flange or bush clearance. A 100% worn link and 100% worn roller tread matched together would cause the roller flange to begin to touch the link pin boss top. As wear proceeds past 100%, wear on the pin boss will reduce pin retention ability and link rebuildability. Wear on the top of roller flanges will reduce their guideability and

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Section 3 - Links Links Link Rail Wear 8

Links are not cracked through in the rail, pin and bush bores or shoe strap sections.

9

Bolt holes are not opened out or elongated to prevent adequate shoe retention.

10

Pin and bush bores are not damaged (broached) as to prevent adequate pin and bush retention.

With proper welding techniques and materials, the fully rebuilt (to 0% worn height) rail should provide about 80% of the original life to the service limit. This percentage may be reduced as impact level increases. By running the rebuilt rail to 120% or destruction it should provide about 100% of the original rail life to the service limit potential.

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Section 3 - Links Links Link Wear Patterns

Link Wear Patterns Rail (Top) Wear

Uneven Scalloping Wear on Rail Top

Normal expected wear position.

Causes (A & C) Faster wear rate due to reduced contact with rollers at narrower link overlap area (also K Rail Side Wear ( T 3-10)).

Causes

Rolling and sliding contact with roller and idler treads.

Accelerators

Weight, speed, impact, abrasiveness, excessive shoe width, overtight track and snaking.

Causes (B)

Sliding wear rate due to reduced contact area with idler at centre of link rail

Effect

Wear limit reached when roller flanges begin to contact top of pin boss.

Accelerators

Remedies

Eliminate or reduce controllable accelerators listed above and rebuild (weld) to desired rail height.

Same as Rail (Top) Wear, particularly over tight track. (K Rail (Top) Wear ( T 3-9)_.

Effect (A & C)

Wear limit over pin boss reached prematurely.

Note: A, B & C; reduces rebuildability and causes vibration in extreme cases.

Remedies

Same as Rail (Top) Rail. (K Rail (Top) Wear ( T 3-9)).

Fig 2.

Fig 3.

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Section 3 - Links Links Link Wear Patterns

Rail Side Wear

Rail Inside Gouged

(Inside and/or outside)

Causes

Sprocket tooth tip interfering due to snaking track and/or misalignment of track or sprocket (see Sprocket Wear).

Causes

Rolling and sliding contact with roller and idler flanges.

Accelerators

Accelerators

Same as "Rail Top Wear" plus uneven terrain, turning, side hill operation, excessive shoe width and snaking track.

Side hill or uneven terrain, turning, excessive shoe width.

Effect

Reduced rebuildability of links and reusability of sprocket if severe.

Effect

Reduces rail wear life to service limit and rebuildability.

Remedies

Correct controllable cause and accelerators.

Remedies

Reduce or eliminate controllable accelerators, particularly snaking track, tight track and wide shoes.

Fig 5.

Fig 4.

Pin Boss Top Worn Causes

Sliding and roller contact with roller flange tops (see Roller Flange Wear).

Accelerators

Non uniform front and rear roller wear when link is not 100%.

Effect

Loss of pin retention and reduced rail rebuildability.

Remedies

Swap rollers to balance wear effect and rebuild rail, rollers as required.

Fig 6.

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Section 3 - Links Links Link Wear Patterns

Elongation of Counterbore

Depth Wear in Counterbore

Causes

Rotating contact with the bush end in pitch extended track (see Track Bush Counterbore Wear).

Accelerators

Non - a direct function of pitch extension.

Effect

Reduces re-sealability of counterbore.

Link is less rebuildable.

Remedies

Turn pins and bushes in track at service limit.

Causes

Rotative contact between track or bush end with bottom of counterbore.

Accelerators

Abrasiveness, side hill loads and turning, side thrust impact and excessive shoe width.

Effect

Same as Counterbore elongation wear (K Elongation of Counterbore ( T 3-11)).

Remedies

Reduce or eliminate controllable accelerators and install new seals at pin and bush turn time.

Fig 7.

Fig 8.

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Section 3 - Links Links Link Wear Patterns

Face Wear

Pin Boss End - Guiding Guard Wear Rotative contact between overlapping link faces following track link counterbore depth wear and bush end wear which allows end play.

Causes

Sliding contact between pin boss ends and guiding and roller guards.

Accelerators

Sliding wear rate due to reduced contact area with idler at centre of link rail.

Accelerators

Abrasiveness, side hill loads and turning, side thrust impact and excessive shoe width.

Effect

Reduces pin retention and therefore limits rebuidability.

Effect

Reduces wear life of original and/or rebuilt link and reduces rebuildability.

(Also K Rail (Top) Wear ( T 3-9)).

Remedies

Remedies

Reduce or eliminate accelerators.

Reduce or eliminate all controllable accelerators related to loads conveyed from shoe link. Keep bolts properly torqued and use narrowest shoe possible.

Causes

Fig 10.

Fig 9.

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Section 3 - Links Links Link Structural Problems

Link Structural Problems Rail Chipping or Flaking

Link Cracking

Causes

Repeated high impact contact with roller treads and/or flanges.

Causes

Repeated twisting of link.

Accelerators

Accelerators

impact, machine speed, weight, excessive shoe width and overtight track.

Effect

May reduce wear life rebuildability if over 30% of rail surface is affected otherwise only a cosmetic effect.

Same as "Rail Chipping or Flaking" plus degree of rail material worn away.

Excessive shoe width is biggest accelerator.

Effect

Shortens link assembly life, track separation if cracked through and prevents rebuilding.

Remedies

Reduce or eliminate controllable accelerators particularly wide shoes and overtight track.

Remedies

Reduce or eliminate controllable accelerators, particularly wide shoes, that add weight and leverage loads on uneven terrain.

Fig 12.

Fig 11.

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Section 3 - Links Links Link Structural Problems

Pin & Bush Bore Enlargement Causes

Bore material broached out during assembly and/or disassembly; plus material worn out during sliding movement of flexing pins and bushes.

Accelerators

Same as "Rail Chipping or Flaking" plus material worn off of pin bosses.

Excessive shoe width is biggest accelerator.

Remedies 1

Improved track press alignment and tooling to prevent broaching during assembly and disassembly.

Remedies 2

Reduce or eliminate controllable accelerators especially wide shoes and overtight track.

Fig 13.

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Section 4 - Track Pins & Bushes Track Pins & Bushes Track Bush Wear

Track Pins & Bushes Track Bush Wear Measurement Technique

Caliper Squeezed Too Tight

The track bush is the most important component in the undercarriage to measure and interpret accurately. To do this, use the caliper provided with the JCB tool kit.

Caliper Method

Fig 2. – Calipers that are over tightened can spread like a spring and will give too small a reading.

Caliper At Wrong Angle To Bush Axis

Fig 3.

Fig 1.

This method gives a direct reading of bush diameter. With careful cleaning and proper technique it can yield the most accuracy, but is also the most susceptible to error if not properly measured.

– Calipers that are set at an angle to the bush will give an oversize measurement.

The most common errors using the caliper are;

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Section 4 - Track Pins & Bushes Track Pins & Bushes Track Bush Wear Caliper Not Slid Back And Forth Across Position To Be Measured.

Calipers Not Placed At Most Worn Portion Of Bush.

Fig 6.

Fig 4.

– Caliper that are not passed back and forth over the maximum diameter of the bush position being measured will give an undersize reading.

– If the caliper is located inboard or outboard of the minimum diameter along its length in a given wear position the reading will be oversized.

The best way to practice measuring bush wear is with bushes removed from the track. you should be able to repeat the measurement made by yourself and others with an accuracy of +0.25 mm (+0.01 in)

Bush Not Cleaned Well Before Measurement.

As varying amounts of internal wear takes place, the external wear pattern will change positions and accelerate, thus reducing its life due to greater interference loads with sprocket and greater sliding motion against the sprocket.

Fig 5.

– If the bush surface is not cleaned the measurement taken will be oversized.

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Section 4 - Track Pins & Bushes Track Pins & Bushes Track Bush Wear Measurement Technique The small caliper must be used to measure the wear at the minimum diameter of the bush regardless of the position with respect to vertical and forward or reverse. This is because the track bush must have sufficient strength to resist cracking after turning. This remaining strength is largely affected by wear before turning. Also, the track bush receives most of is load in the later part of wear life in the position where the maximum wear is.

Fig 7.

Wear Limits - Service and Destruction As mentioned in Measurement Technique, wear limits for track bushes are determined not only on the basis of remaining strength before and after turning but also the external wear in later hours. The "high impact" allowable wear to the service point is 3.1 mm (0.12 in). The "low impact" allowable wear to service point is 4.8 mm (0.19 in).

Destruction (break through) is expected to occur within 20% of any additional hours if the same condition exists.

Wear limits should always be chosen on the basis of degree of expected impact, not on the basis of abrasiveness or desired life.

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Section 4 - Track Pins & Bushes Track Pins & Bushes How to Interpret Wear on Track Bushes

How to Interpret Wear on Track Bushes Since the successful turnability and total life of track pins and bushes is a function of both internal and external wear, interpretation of the external bush wear alone will not accurately determine if and when to turn. However, the type and degree of external bush wear is a good indicator of abnormal problems.

Forward Drive Side Wear Critical (30째 to 65째 from vertical) Causes

Rotation and sliding against sprocket under abnormal forward loads (characteristic of push loading, drawbar, ripping and dozing application).

Accelerators

Same as Reverse Drive slide Critical (K Reverse Drive Side Wear Critical ( T 4-18). Plus uneven terrain and worn rear rollers.

Effect

Bush wall worn through at same position as internal wear occurring and may result in need for turn before service point to avoid cracking if internal wear is critical. It will not have same effect on after-turn life of bush as does critical reverse drive side wear.

Remedies

Eliminate or reduce controllable accelerator causes such as overtight track and worn rear rollers. Turn early if initial wear is critical to prevent bush cracking.

External Wear - Assembled or Disassembled Track Shown here are typical patterns for later normal conditions where internal wear has begun to have a measurable pitch extension effect on the external pattern.

Reverse Drive Side Wear Critical (30째 to 65째 from vertical) Causes

Rotation and sliding against sprocket under abnormal load (characteristic of track loaders).

Accelerators

Weight and speed; impact, abrasiveness, overtight track and high reverse working loads.

Effect

Cracks will occur on reverse drive slides which become forward drive slides after bush is turned and will reduce the total turned life of the bush.

Remedies

Eliminate or reduce controllable accelerator causes. Do not delay turn past service point (100%) if turn is required. Also do not drive machine long distance in reverse.

60 30 Fig 9.

65 30 Fig 8.

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Section 4 - Track Pins & Bushes Track Pins & Bushes How to Interpret Wear on Track Bushes Forward Drive Sides (FDS) and Reverse Drive Sides (RDS) Critical Compared to Vertical

Other Wear Patterns-Disassembled Track End Wear

(30° to 65° from vertical)

Bush End Wear

Causes

Sliding motion of bush against sprocket under abnormal interference loads (characteristic of high internal wear in any application or condition).

Accelerators

Same as 2FDS and RDS Critical" described above especially track which has been over tightened to compensate for snaking.

Effect

Can cause bush cracking before or after turn if service point is exceeded.

Remedies

Eliminate or reduce controllable accelerator causes, especially overtight track and turn based on internal wear at service point.

Causes

Sliding or abrasive contact between inside seal and link counterbore bottom (usually directly related and a result of the degree of internal wear and snaking and not a cause of snaking).

Accelerators

All machine weight and speed related loads; all loads related to side thrust caused by terrain and manoeuvring; abrasiveness. The only controllable accelerator variables are shoe width and condition of guiding components.

Effect

Reduces re-sealability of joint at turn time. Reduces internal wear life and link rebuildability after turn.

Remedies

Turn pins and bushes at service limit.

Keep guiding components in good condition.

60

60 30

30 Fig 10.

Fig 11.

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Section 4 - Track Pins & Bushes Track Pins & Bushes How to Interpret Wear on Track Bushes

Structural Problems on Bushes

Bush Counterbore Wear (RDS only) Causes

Rotational sliding contact with RDS of link counterbore and abrasives (always directly related to and a result of internal wear pitch extension, not a cause or result of snaking).

The destruction limitation of a track joint is usually due to structural failure in the bush caused by cracking or loosening after internal and/or external wear limits are exceeded. The most common causes, accelerators, effects and remedies are shown here.

Accelerators

Same as"Internal Pin and Bush Wear."

Bush Cracks (Through the entire wall)

Effect

Reduces re-sealability of joint. Reduces internal wear life and link rebuildability after turn.

Remedies

Same as"Internal Pin and Bush Wear."

Causes

Exceeding internal wear limit and/or exceeding external wear limit for respective degree of impact. (Crack can be in several positions and configurations).

Accelerators

Any loads between sprocket and bush caused by weight, speed, impact and terrain, excessive shoe width, worn rear rollers, overtight track and exceeding internal wear limits are primary controllable causes.

Effect

Depending on degree of cracking and/or loss of bush wall material, bush may not have strength to provide wear life potential of after turn.

Remedies

Eliminate or reduce controllable accelerator causes.

Fig 12.

Fig 13.

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Section 4 - Track Pins & Bushes Track Pins & Bushes How to Interpret Wear on Track Bushes Bush End Cracks Causes

impact contact with counterbore following internal wear and snaking.

Accelerators

Same as"Bush End Wear" and "Bush Counterbore Wear"

Remedies

Do not exceed internal wear service limits.

Fig 14.

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Section 4 - Track Pins & Bushes Track Pins & Bushes Track Pitch Internal Wear

Track Pitch Internal Wear Measurement Technique Track internal wear is measured by determining the pitch extended length over four adjacent sections with a tape measure calibrated in 0.5 mm (0.021 in) increments. The track and tape must be stretched tight and straight to obtain an accurate measurement. This can easily be achieved by placing a pin (an old track pin) in the sprocket tooth as shown (K Fig 15. ( T 4-22)) and rotating the track so that the track is tensioned.

The calibrated side of the tape should be located along an imaginary line which connects the pin centres. The reading should be made from one side of a pin to the same side of the fifth pin away (which includes 4 links). the hook at the beginning of the tape should not be used and the mark at an even increment of centimetres or inches should be placed on the 5th pin leaving the end of the tape free to measure the fractional part of the total length. This measurement should be taken at least 3 sections away from a master link joint and should be repeated at least twice over different sections of the track on both sides of the machine. This measurement can be used directly to find the percent worn in the charts.

Fig 15.

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Section 4 - Track Pins & Bushes Track Pins & Bushes Track Pitch Internal Wear

Wear Limits to Service and Destruction and Percent Worn Chart The detrimental effects of excessive pitch extended track are related to the following factors: – Counterbore depth and elongation wear which accelerate wear rates and prevent adequate resealing after turning or pin and bush replacement, shortening after turning or after replacement pin and bush life.

– Track snaking damage to other components which shorten their total life potential and rebuildability.

– Tendency of users to over tighten track to "compensate" for snaking or excessive pitch extended track and its effects on bush, sprocket and other components.

– Loss of strength to bush wall internally which contributes to bush cracking in FDS (Forward Drive Side) before turning when FDS external wear is critical and on FDS after turning when RDS (Reverse Drive Side) external wear was critical before the turning.

The destruction point of internal wear for projection purposes is defined as 120% of service limit in "high" impact conditions.

Since "destruction point", as related to internal wear, actually results in external bush break-through (which is also a result of external wear) both internal and external worn percent must be known to make an accurate projection of the destruction point.

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Section 4 - Track Pins & Bushes Track Pins & Bushes Wear and Structural Problems on Track Pins

Wear and Structural Problems on Track Pins Pin O.D. (External) Wear [and Bush I.D. (Internal) Wear] Causes

Rotational contact with abrasive material and/or I.D. of bushes.

Accelerators

Weight and speed of machine; abrasiveness, loss of sealing effect and snaking, impact, terrain packing loads, and manoeuvring. Track tension, excessive shoe width, worn rear roller and high speed non-productive work are the main controllable causes.

Effect

Track pitch increases with resulting mismatch. See Bush and Sprocket Wear. Beginning of "chain-reaction" of most advanced undercarriage component wear.

Remedies

Eliminate or reduce controllable accelerator causes, turn sealed track pins and bushes at service limit.

Pin End Wear Causes

Sliding contact with guiding and/or roller guards plus abrasives (may be seen at either or both ends of pin - usually more severe on outboard side).

Accelerators

Uneven terrain and side hill operation.

Excessive shoe width, worn rolling component, flange misalignment and snaking track are the main controllable causes.

Effect

Pin will have to be re-chamfered before re-assembling track at turn time to avoid broaching link pin bore with sharp edges resulting in pin retention loss.

Extreme cases will show wear on the outer face of pin boss which reduces pin retention.

Remedies

Eliminate or reduce controllable accelerator causes, particularly snaking track by turning pins and bushes.

RDS

FDS

Fig 16.

4 - 24

FDS

Fig 17.

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Section 4 - Track Pins & Bushes Track Pins & Bushes Wear and Structural Problems on Track Pins

Pin Loosening

Pin Breakage

Causes

Loss of press fit retention in link pin bore.

Accelerators

(1) Severe repeated impact yields or cracks link bore. (2) Uneven terrain and excessive shoe width increase flexing of pin in bores. (3) Link bore broached by improper track press alignment at reassembly time. (4) Loose track shoes.

Effect

Loss of pin and separation of track; loss of parts reusability and rebuildability.

Remedies

(1) Eliminate or reduce controllable causes which increase impact loads and flexing of joint such as excessive shoe width. (2) Control track press alignment capability and re-chamfer worn pin ends to reduce bore broaching.

Causes

High static or impact loads which cause crack to start at outer surface (usually at pin wear step) and moves through entire pin at a fast rate.

Accelerators

Weight and speed of machine. impact and terrain conditions. Amount of internal wear that reduces pin diameter. Overtight track, excessive shoe width, worn rear rollers and severe packing loads caused by rocks between bush and sprocket are main controllable causes.

Effect

Immediate track separation. Severe damage to other components.

Remedies

Eliminate or reduce controllable accelerator causes, particularly rocks which are getting into spaces between sprocket and bushes.

Fig 18.

Fig 19.

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Section 4 - Track Pins & Bushes Track Pins & Bushes Wear and Structural Problems on Track Pins

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Section 5 - Shoes Shoes Shoe Structural Problems

Shoes Shoe Structural Problems All shoe structural problems described here should be considered for their own cause plus the effect on the rest of the undercarriage components.

Shoe Bending, Cracking and Breaking Causes

Bending load on shoe exceeds shoe beam strength due to; (1) Loss of grouser and plate wear material. (2) Shoe too wide for underfoot conditions.

Bolt Hole Opening Out (With loose hardware) Causes

Loss of clamping between shoe and link or loose bolt pounds hole larger.

Remedies

(1) Choose narrowest shoe which will give adequate flotation. (2) Tighten (and retighten) hardware if necessary according to proper torque procedure and specifications.

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Section 5 - Shoes Shoes Shoe Structural Problems

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Section 6 - Idlers Idlers Idler Tread wear

Idlers Idler Tread wear Measurement Technique

Wear Limits - Service and Destruction

Tread wear is the only measurable wear position on the idler. It is determined by measuring with the broad based depth gauge from the idler centre flange to the tread surface. The positioning of the depth gauge should be so that the measurement rule is aimed as close as possible towards the centre of the idler with the base flat on the centre flange and parallel to the idler shaft. The greatest error in measuring idler wear arises from wear on top of the centre flange which alters the reference point. Abrasive packing conditions usually cause the greatest amount of centre flange wear. If this wear is suspected some attempt to compensate for it should be made in the reading taken.

Remember idler tread wear measurements increase as tread wear occurs and decrease as centre flange wear occurs.

Idler tread allowable wear and resulting wear limits are based on two basic criteria: Rebuildability of the tread surface plus centre flange to track bush clearance. As wear proceeds past 100% each of these considerations may result in damage to other parts. If the idler is worn 120% the tread will become too thin to successfully rebuild. The 120% worn or destruction limit will be reached at approximately 20% more hours than it took to reach service limit (100%) in similar conditions.

Wear Charts for idlers are a direct reading from the measurement taken. They have a built-in factor allowing for faster wear rate after the case hardened depth is worn away. As with links and rollers, the wear rate is about three times as fast in the unhardened material below the case hardening depth, with a transition rate between. Beyond the service limit, the wear rate is increased to an even faster rate because of the expected additional sideways sliding motion between links and tread as the centre flange sides become worn.

Fig 1.

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Section 6 - Idlers Idlers Idler Wear Patterns

Idler Wear Patterns Idler wear patterns can be used to help interpret abnormal wear causes on mating parts, track links, plus interpret other controllable and non-controllable accelerator causes, which may be affecting non-mating parts such as rollers which are harder to see and inspect.

Flange Side Wear Causes

Engagement motion with track link inner rail side.

Accelerators

Same as "Tread Wear" except terrain (hill side) turning and misalignment have a much greater result on flange side (see discussion on idler alignment).

Track tension, snaking track and worn front guiding guards also have greater results on flange sides than treads.

Shoes which are too wide also contribute.

Effect

Reduces idler tread rebuildability due to (welding) difficulty. Effect on link rail inside is more important than effect on idler itself however.

Remedies

Reduce or eliminate controllable accelerator causes including misalignment, worn front guiding guards, snaking track, overtight track and excessively wide shoes.

The idler tread wear rate is very sensitive to track overtightness

Tread Wear - Normal wear pattern Causes

Sideways sliding motion with track link rail surface.

Accelerators

Machine weight, speed, and applications which put more weight on the front of the machine. impact, abrasiveness, packing, terrain and turning. Overtight and/or snaking track are main controllable causes.

Effect

If worn past 100% at deepest part may reduce rebuildability and may crack at 120% or more worn.

Remedies

Reduce or eliminate overtight track and correct misalignment problems as indicated by off-centre wear pattern.

Rebuild treads when service limit reached.

Fig 3.

Fig 2.

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Section 6 - Idlers Idlers Idler Wear Patterns

Flange Top Wear (may be domed) Causes

(1)Sliding contact with any abrasive material packed into idler assembly area. (2) impact contact and motion with track links which have jumped out of tread area.

Accelerators

Speed, packing, adhesion and abrasiveness of packed material.

Tracks which are too loose or snaking increases chances of track link damage.

Effect

Reduces wear measurement distance and resulting accuracy. Reduces rebuildability in extreme cases.

Remedies

Rebuild if critical. Clean packed material away from area behind the idler. Correct cause of links jumping out of tread and running on centre flange if this wear is present in absence of packing.

Fig 4.

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Section 6 - Idlers Idlers Idler Wear Patterns

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Section 7 - Carrier Rollers Carrier Rollers Carrier Roller Tread Wear

Carrier Rollers Carrier Roller Tread Wear Measurement Technique

Wear Charts

Track carrier roller tread wear is the easiest to measure and interpret of any undercarriage wear. It is measured by determining the diameter with large callipers as a rule.

Wear charts for carrier rollers are a direct reading from the diameter measurement. They have a built in factor for faster wear rate expected after the case hardening is worn through. For some sizes the case hardening covers the entire allowable wear so that the expected wear rate is uniform.

Care should be taken to find the diameter and position representing the most worn (smallest true diameter) as it is that wear which determines when service and/or destruction limits are reached. Measurements should be made to the closest 0.25 mm (0.01 in).

Rebuildability carrier rollers with forged steel rims (most machines) should be rebuildable assuming flange wear or damage is not critical.

The primary cause of a non rebuildable carrier roller is flat spots worn on the tread. This is caused by links sliding over the tread on non-turning stuck carrier rollers, usually in the presence of severe packing.

Fig 1.

Wear Limits - Service or Destruction Carrier roller allowable wear and resulting wear limits are based on two primary factors: First, to prevent flange interference with the track bush and second, to insure remaining strength and successful rebuildability of the carrier shell itself. When 100% worn to the service limit, flanges will not contact the bush even with a 100% worn link but beyond that point and certainly by 120% worn structural failure could result to the bush and the carrier roller.

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Section 7 - Carrier Rollers Carrier Rollers Carrier Roller Wear Patterns

Carrier Roller Wear Patterns There are three principle wear patterns found on carrier rollers. In each case the effect on the link may be more critical, considering total undercarriage life, than on the carrier rollers themselves.

Uneven Flange Side Wear and Offcentre Tread Wear Causes

Rolling and sliding contact with link rail top and sides not aligned with carrier roller.

Accelerators

same as "Carrier Roller Tread Wear" plus terrain and sidehill; and misalignment of carrier rollers, sprocket and/or idler. Offset shoes will move track to outboard side.

Effect

Loss of potential wear life and rebuildability of carrier roller links.

Remedies

Reduce or eliminate controllable accelerators. Swap carrier roller to balance wear.

Tread Wear (Uniform) Causes

(1) Rolling and sliding motion with link rail (top) surfaces. (2) Sliding contact with packing material on roller frame.

Accelerators

Machine speed. Weight of track which is governed by shoe width, including packing material. Track tension is a primary controllable variable as a tight track increases load and a loose track causes impact between links and tread surface, particularly in forward motion.

Effect

Wear life of carrier roller and links. No other components affected unless service limit exceeded, then flanges may strike bushes causing unusual wear pattern and premature failure.

Remedies

Maintain proper track tension and reduce or eliminate other controllable accelerator causes. Rebuild or replace carrier roller shell when service limit reached.

Fig 3.

Fig 2.

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Section 7 - Carrier Rollers Carrier Rollers Carrier Roller Wear Patterns

Flat Spots on Tread Causes

Sliding contact with link rail tops when carrier roller not turning.

Accelerators

same as "Even Tread Wear" packing between roller frame and carrier roller is principle cause of sticking.

Effect

Reduced wear life and rebuildability of carrier rollers. Accelerated wear on links.

Remedies

Clean packing material away from carrier.

Fig 4.

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Section 7 - Carrier Rollers Carrier Rollers Carrier Roller Wear Patterns

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Section 8 - Track Rollers Track Rollers Roller Tread Wear

Track Rollers Roller Tread Wear Track roller wear is the most difficult of all to measure and interpret. In some cases not all measurements will be possible. Several assumptions and correlations may have to be made to better interpret the roller system wear condition in the absence of complete measurements of inner and outer flanges on all rollers. The measurement techniques recommended here are reliable and safe methods of obtaining wear measurements. Certain modifications of measurement tools may make this measurement easier, but will not increase the accuracy.

Caliper Squeezed Too Tight

Tread Measurement Technique Track roller tread wear can be measured by using a large caliper as described below:

Caliper Measurement

Fig 2. – Calipers that are over tightened can spread like a spring and will give too small a reading.

Fig 1.

1

Position the caliper, where possible, so that the tongs or tips of the caliper are touching the tread in its most worn position on the diameter.

2

Pass the caliper back and forth to find the true minimum diameter.

The most common errors using the caliper are;

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Section 8 - Track Rollers Track Rollers Roller Tread Wear Caliper Not Slid Back And Forth Across Position To Be Measured.

Front and Rear Rollers Most Important If roller guards or other conditions prevent the measurement of all rollers, then the most important roller to be measured or estimate wear on is the rear roller. The next most important roller to be measured is the front roller.

These two rollers should definitely be inspected by any means possible that does not present a safety hazard. The rear and/or front rollers generally will be most worn and therefore critical in maintenance and servicing decisions.

Wear Limits - Service and Destruction

Fig 3. – Caliper that are not passed back and forth over the maximum diameter of the bush position being measured will give an undersize reading.

Bush Not Cleaned Well Before Measurement.

Fig 4. – If the bush surface is not cleaned the measurement taken will be oversized.

Failure To Measure Both Outer AndInner Treads. – This may lead to understating the effect of wear on the roller if the inner tread is more worn.

Allowable wear on roller treads and resulting wear limits have been determined as for the link, by allocating some fraction of the roller flange to pin boss (or bush) clearance as appropriate. This is based on the assumption that the average roller wear will equal link wear. Since front and/or rear rollers usually wear at a faster rate than centre rollers it should be assumed that the front and rear rollers will reach service or destruction limit prior to links and therefore be the first cause of pin boss to roller flange interference. For example, 90% worn links may still experience pin boss to roller flange interference even though average roller wear is only 90% because the rear roller is 110% worn. (see Roller Swapping Guidelines").

Pin boss to roller flange interference results in wear on top of the roller flanges, thus reducing the rebuildability and strength of the flanges.

When the roller tread is past worn the service limit (100% worn) its weldability is also reduced. As wear approaches 120% worn, structural damage to the roller shell is in the form of cracking or breaking my result due to loss of strength.

Wear Charts Like links, roller tread wear charts have a built in factor to account for an expected faster wear rate after the case hardened depth is worn away. The wear rate after the case hardening will be approximately three times as fast as when the roller is new.

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Section 8 - Track Rollers Track Rollers Roller Wear Patterns

Roller Wear Patterns Roller wear patterns may be used as indicators of abnormal controllable conditions that may affect other parts in the undercarriage. The wear patterns shown here are mostly found in a combined pattern with varying degrees of each depending on the causes.

Tread Wear (Normal wear pattern) Causes

(1) Rolling contact with abrasives crushed between roller tread and rail (top) surface. (2) Sideways sliding contact between rail and tread.

Accelerators

Weight, machine speed, impact, abrasiveness, and to some extent packing. Terrain and application often determine unbalanced inner to outer tread and front to rear roller wear rates.

Unusual roller frame distortion problems can accelerate selective wear rates.

Turning increases sideways sliding contact. Excessive shoe width and track snaking tends to accelerate rounded patterns.

Effect

Pin boss to roller flange interference when link and roller combined service limit reached or exceeded.

Remedies

Reduce or eliminate controllable accelerator causes particularly nonproductive turning and wide shoes.

Swap rollers to balance final wear lives.

Rebuild (weld) rollers to dimensional level.

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Fig 5.

8 - 39

Section 8 - Track Rollers Track Rollers Roller Wear Patterns

Flange Side Wear (Inner and/or outer sides facing tread)

Flange Top Wear

Note: Machines may or may not have inner flanged bottom rollers

Note: Machines may or may not have inner flanged bottom rollers Causes

Causes

Rolling and sliding contact with rail sides.

Accelerators

Same as "Tread Wear" except side hill operation, uneven terrain, turning misalignment, worn guiding guards, snaking track and excessive shoe width have greater measurable result on flange than on tread.

Effect

Reduces guideability and rebuildability of rollers.

Remedies

Same as "Roller Tread Wear".

Rolling and sliding contact with link pin bosses after loss of clearance.

Accelerators

Same as "Tread Wear" .

Effect

Reduces roller rebuildability. Damages link pin bosses with resulting pin retention and rebuildability loss.

Remedies

Same as "Roller Tread Wear".

Fig 7.

Fig 6.

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Section 9 - Sprockets Sprockets Sprocket Wear

Sprockets Sprocket Wear The Function of the sprocket wear gauge is to indicate whether there is sufficient wear material left in the sprocket tooth to provide structural life to match the expected remaining bush life that will be used with it following a bush turn or replacement It is used on or near bush turning or replacement time only (bush turned or replaced at 90-110% worn) The past and projected sprocket life should be thought of in terms of the bush (sides) of life it has or will be expected to provide, not in terms of actual hours on the sprocket itself.

Fig 1.

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Section 9 - Sprockets Sprockets Sprocket Wear Patterns

Sprocket Wear Patterns The sprocket wear gauge makes interpretation of sprocket tooth profile wear patterns much easier. Also, sprocket wear patterns should be used only to help determine the cause and effect of corresponding bush wear patterns since the gauge will indicate sprocket reuse.

As noted previously, the sprocket wear gauge ignores sprocket tooth tip condition as the tooth tip is not a criteria for the remaining functional strength and wear life of the sprocket or how it will adversely affect the bush after reuse.

The sprocket gauge locates low on the tooth side, as wear here determines: 1

The remaining strength in the tooth to support further bush wear in the driving portion of the tooth.

2

The degree of expected sliding the bush will be expected to incur thus affecting its expected wear rate.

Root Wear (0-30 degrees from vertical) is a normal expected wear pattern of a track in the absence of severe packing and prior to pitch extension.

Causes

Sliding contact with vertical position of bush during forward to reverse direction changes and due to pitch mismatch of minor packing effect and/or advanced component wear.

Accelerators

See "Bush Vertical Position" wear.

Effect

Non on sprocket itself. In absence of other wear patterns, improves sprocket reusability.

Remedies

Eliminate or reduce controllable causes shown under vertical position bush wear. Objective should be to extend bush life, not sprocket life in this position.

The wear patterns shown here should not be assumed to be a result of sprocket wear characteristics alone, and therefore corresponding bush wear pattern should be studied. See the section entitled “Track Bush Wear.�

Also, since some sprocket wear patterns, (particularly on the outside surfaces and tips that face the links) are a result of snaking track, guiding and alignment problems, the sections covering those situations should also be consulted.

30

0

30

Fig 2.

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Section 9 - Sprockets Sprockets Sprocket Wear Patterns

Reverse and/or Forward Drive Side Wear

Reverse Drive Side Tip Wear

(30-60 degrees from vertical) is a normal expected wear pattern of a track with track pitch extension with or without packing.

(Corresponding to more than 60° from vertical on bush wear).

Causes

Causes

Sliding contact with corresponding bush position. It indicates combined degree of mismatch resulting from internal wear plus packing.

Accelerators

See "RDS and FDS wear on Track and Bushes" .

Effect

Reduces potential wear life of sprocket segment due to reduced strength of tooth in driving position.

Remedies

Reduce or eliminate controllable accelerator variable listed under " Bush FDS and/or RDS Wear" positions.

Change sprocket as indicated by sprocket wear gauge at bush turn or replacement time only. Action taken should be related to the bush, not the sprocket except in extreme cases when loss of tooth could cause final drive damage.

60

60 30

Note: To determine the cause of packing on a track which is too loose note the direction of the scratches on the tooth tip. If the point toward the tip then the cause is probably a loose track; if they point toward the foot, the cause is probably severe packing.

Accelerators (1) For packing - same as "Bush FDS and/or RDS Pockets". (2) For track too loose - same as "Bush FDS and/or RDS Pockets" except track tension needs to be increased by removing excess slack.

Effect

(1) & (2) No adverse effect on sprocket itself when in absence of other significant FDS and/or RDS wear patterns. Does not affect sprocket reusability or ultimate wear life as FDS/RDS wear should take take over as most worn positions with track following pitch extension.

Remedies

(1) If caused by packing - reduce or eliminate controllable accelerator causes, particularly overtight track. use sprocket reusage gauge to determine versatility following bush turn or replacement. (2) If caused by loose track - adjust track to proper tension. Use sprocket wear gauge to determine following bush turn or replacement.

30 Fig 3.

9 - 43

(1) Severe packing effect, in the absence of track pitch extension, causing bush to have interference with sprocket tooth tip upon entry at the bottom of the sprocket in forward motion and/or interference with tooth tip upon exit at the bottom of the sprocket in reverse motion. Track too loose; track with more than 25 mm (1 in) [19 mm (3/4 in) on one carrier roller machines] of slack results in "back jamming" the bush at the bottom of the sprocket in reverse motion.

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Section 9 - Sprockets Sprockets Sprocket Wear Patterns

Sprocket Side Wear and Corner Wear or Gouging (Inner and/or Outer) Causes

(1) If Inner or Outer sides are over 360° of sprocket, principle causes are snaking track. (2) If limited to inner or outer, or not uniform over 360° of sprocket then principle cause is probably misalignment of sprocket and/ or roller frame.

Forward Drive Side Tip Wear

Accelerators

Uneven terrain and side hill; turning, excessive shoe width, snaking.

Causes

Effect

Principle adverse effect is on link (see "How to Interpret Link Wear Patterns"). Severe cases reduce contact area of sprocket-bush fit and may accelerate bush wear. Also may cause an offcentre bush wear pattern if the cause is alignment.

Remedies

(1) If caused by snaking track, pins and bushes should be turned or replaced but main consideration is track, not sprocket wear. (2) If caused by worn guiding guards replace wear strips.

60 Fig 4.

Bush sliding interference due to mislocation of bush in very severe packing with track with little internal wear. Occurs at top of sprocket in forward (exit) and reverse (entry) motion. Usually less severe than but always in presence of "RDS Tip Wear" described previously. See K Reverse Drive Side Tip Wear ( T 9-43).Accompanied by bush FDS pocket wear.

Accelerations

Same as "Vertical Position" and " FDS and RDS Bush Wear" except degree of packing is more severe.

Effect

Non on sprocket itself. Does not affect sprocket internal wear life or reusability except in very severe cases.

Remedies

Same as for "RDS Sprocket Tip Wear" described previously where cause is packing. Use sprocket wear gauge to determine reusability at bush.

Fig 6.

REV Fig 5.

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Section 10 - Guards Guards Guiding Guard Wear

Guards Guiding Guard Wear End and centre guiding guards have no definite measurement technique, service limits or wear charts.

They should however be part of every undercarriage inspection and their condition should be described in subjective but comparative terms.

Guiding guards wear on pin ends is a good indicator of guiding guard condition but should not be assumed to be the only indicator since wear strips might have been replaced since the track was first installed.

Guiding guard replaceable wear strips should be replaced before any wear or damage is done to the guard itself. The most convenient time to check and maintain guard wear strips is at pin and bush maintenance and track replacement.

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Section 10 - Guards Guards Need For Roller Guards

Need For Roller Guards Although roller guards (full or partial type) do provide some additional guiding effect their use should be based on the need to keep rocks and/or other foreign debris from entering the roller areas.

Roller guards should not be used therefore when working on packing materials or in any conditions where there is no danger of rocks and debris entering the spaces between the rollers and causing roller, link, bush or sprocket structural damage.

Roller guards should be considered when working in the following types of materials only, and when structural damage to rollers, links, bushes and sprocket has been or may be a problem.

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Section 10 - Guards Guards Conditions For Considered Use Of Roller Guards

Conditions For Considered Use Of Roller Guards – Rocks or gravel of 25 mm (1 in) or larger up to 150 mm (6 in).

– Tree limbs, branches or other no extrudable wood products or waste materials.

– Refuse, landfill and demolition materials only if large metal, wood or other high strength objects of 25150 mm (1-6 in) in size are frequently encountered.

Remember, roller guards should only be used to keep foreign objects out, not for their increased track guiding contribution.

The disadvantages of using roller guards in the wrong conditions or the wrong reasons are: – Difficulty in measuring, inspection and maintaining rollers.

– Helps to keep packing material in - doesn't help to keep it out.

– May unnecessarily increase wear on link rail sides, pin bosses and on pin ends.

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Section 10 - Guards Guards Conditions For Considered Use Of Roller Guards

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Section 11 - Service Information Service information Bush Wear Guide (Ital Track)

Service information Bush Wear Guide (Ital Track) Model

JZ70

JS460

Normal Pitch Wear (%)

Dimension A (mm)

0%

41.3

71.4

10%

41.0

71.0

20%

40.6

70.6

25%

40.5

70.4

30%

40.3

70.2

40%

39.9

69.8

50%

39.5

69.3

60%

39.0

68.8

70%

38.6

68.3

75%

38.3

68.0

80%

38.1

67.7

90%

37.6

67.1

100%

37.0

66.5

110%

36.4

65.9

120%

35.9

65.2

B C A D Fig 1.

Key

11 - 49

B

Forward Side Drive Wear

C

Radial Wear

D

Reverse Side Drive Wear

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Section 11 - Service Information Service information Bush Wear Guide (Berco Track)

Bush Wear Guide (Berco Track) Model R3

JS70

JS110(1)

JS150

JS200

JS300

701337

704464

712105

JS130HD

JS330

JS450

JS130 From serial No.

699381

XO

JS70

JS130

JS450

JS160-260 Normal Pitch

171.45

175.50

190.00

203.20

Dimension A (mm) Wear (%)

normal High normal High normal High normal High impact impact impact impact impact impact impact impact

0%

50.80

50.80

58.70

58.70

58.70

58.70

66.60

66.60

10%

50.50

50.60

58.40

58.50

58.40

58.50

66.20

66.20

20%

50.40

50.50

58.00

58.10

58.00

58.10

65.80

65.90

30%

50.00

50.20

57.60

57.90

57.60

57.90

65.40

65.70

40%

49.70

50.00

57.10

57.40

57.10

57.40

64.90

65.20

50%

49.20

49.60

56.80

57.10

56.80

57.10

64.60

65.00

60%

48.80

49.40

56.40

56.90

56.40

56.90

64.20

64.70

70%

48.50

49.10

56.00

56.60

56.00

56.60

63.80

64.50

80%

47.70

48.60

55.60

56.60

55.60

56.50

63.40

64.30

90%

46.60

48.00

54.90

56.30

54.90

56.30

62.70

64.10

100%

45.60

47.40

54.10

55.90

54.10

55.90

61.90

63.70

110%

44.80

46.70

53.20

55.20

53.20

55.20

61.00

62.90

120%

43.80

46.10

52.50

54.80

52.50

54.80

60.30

62.50

(1) Figures for this machine apply to replacement components only.

Key

B C

B

Forward Side Drive Wear

C

Radial Wear

D

Reverse Side Drive Wear

A D Fig 2.

11 - 50

9803/3010-4

11 - 50

Section 11 - Service Information Service information Pin & Bush Wear Guide (Ital Track)

Pin & Bush Wear Guide (Ital Track) Model

JZ70

JS460

Normal Pitch Wear (%)

Dimension A (mm)

0%

616.0

863.6

10%

616.0

863.6

20%

616.0

863.6

30%

616.0

863.6

40%

616.0

863.6

50%

616.0

863.6

60%

616.0

863.6

70%

616.0

863.6

80%

616.0

863.6

90%

616.0

863.6

100%

632.0

886.0

110%

648.2

908.6

120%

664.3

931.2

Fig 3.

Note: Tracks must be tight to obtain accurate wear measurement

11 - 51

9803/3010-4

11 - 51

Section 11 - Service Information Service information Pin & Bush Wear Guide (Berco Track)

Pin & Bush Wear Guide (Berco Track) Model R3

JS70

JS150

JS200

JS300

699381

701337

704464

712105

JS130

JS 160 - 260

JS130HD

JS330

171.45

175.50

JS110(1)

JS450

JS130 From serial No. XO

JS70

JS450

JS160-260 Normal Pitch

190.00

203.20

Dimension A (mm) Wear (%)

normal impact

normal impact

normal impact

normal impact

0%

686.80

703.00

761.00

813.80

10%

688.00

704.30

762.30

815.10

20%

689.20

705.60

763.60

816.40

30%

690.40

706.90

764.90

817.70

40%

691.60

708.20

766.20

819.00

50%

692.80

709.50

767.50

820.30

60%

694.00

710.80

768.80

821.60

70%

695.20

712.10

770.10

822.90

80%

696.40

713.40

771.40

824.20

90%

697.60

714.70

772.70

825.50

100%

698.80

716.00

774.00

826.80

110%

701.60

718.50

776.50

829.60

120%

704.20

722.00

779.50

833.00

(1) Figures for this machine apply to replacement components only.

Note: Tracks must be tight to obtain accurate wear measurement

Fig 4.

11 - 52

9803/3010-4

11 - 52

Section 11 - Service Information Service information Track Link Rail Wear Guide (Ital Track)

Track Link Rail Wear Guide (Ital Track) Model

JZ70

JS460

Normal Pitch Wear (%)

Dimension A (mm)

0%

74.0

129.0

10%

73.6

128.3

20%

73.1

127.6

25%

72.8

127.2

30%

72.6

126.8

40%

72.0

126.0

50%

71.5

125.2

60%

70.9

124.3

70%

70.2

123.3

75%

69.9

122.8

80%

69.5

122.3

90%

68.8

121.2

100%

68.0

120

110%

67.2

118.8

120%

66.4

117.6

Fig 5.

Note: Tracks must be tight to obtain accurate wear measurement

11 - 53

9803/3010-4

11 - 53

Section 11 - Service Information Service information Track Link Wear Guide (Berco Track)

Track Link Wear Guide (Berco Track) Model R3

JS70

JS110(1)

JS150

JS200

JS300

701337

704464

712105

JS130HD

JS330

JS450

JS130 From serial No. XO

699381 JS70

JS130

JS450

JS160-260 Normal Pitch

171.45

175.50

190.00

203.20

Dimension A (mm) Wear (%)

normal impact

normal impact

normal impact

normal impact

0%

96.00

103.20

106.00

117.50

10%

95.40

102.00

105.30

117.10

20%

94.90

101.20

104.60

116.40

30%

94.30

100.20

103.90

115.60

40%

93.70

99.20

103.20

114.80

50%

93.30

98.40

102.50

113.80

60%

92.60

97.40

101.90

112.90

70%

92.10

96.40

101.10

112.00

80%

91.40

95.40

100.20

110.80

90%

90.80

94.60

99.50

109.30

100%

90.00

93.70

98.80

108.50

110%

89.30

91.30

97.80

107.90

120%

88.60

89.00

97.00

106.00

(1) Figures for this machine apply to replacement components only.

Fig 6.

Note: Tracks must be tight to obtain accurate wear measurement

11 - 54

9803/3010-4

11 - 54

Section 11 - Service Information Service information Upper Roller Wear Guide (Ital Track)

Upper Roller Wear Guide (Ital Track) Model

JZ70

JS130/240

JS330/460

Normal Pitch Wear (%)

Dimension A (mm)

0%

86.0

120.00

145.0

10%

85.5

119.7

144.5

20%

85.0

119.3

143.9

25%

84.7

119.1

143.5

30%

84.4

118.9

143.2

40%

83.8

118.4

142.5

50%

83.1

118.0

141.7

60%

82.4

117.5

140.9

70%

81.7

116.9

140.0

75%

81.2

116.6

139.6

80%

80.8

116.3

139.1

79.9

115.7

138.0

79.0

115.0

137.0

110%

78.1

114.3

135.9

120%

77.2

113.7

134.9

A

90% 100%

Fig 7.

11 - 55

9803/3010-4

11 - 55

Section 11 - Service Information Service information Upper Roller Wear Guide (Berco Track)

Upper Roller Wear Guide (Berco Track) Model R3

JS70

JS110(1)

JS150

JS200

JS300

701337

704464

712105

JS130HD

JS330

JS450

JS130 From serial No. XO

699381 JS70

JS130

JS450

JS160-260 Normal Pitch

171.45

175.50

190.00

203.20

Dimension A (mm) Wear (%)

normal impact

normal impact

normal impact

normal impact

0%

120.00

120.00

120.00

145.00

10%

118.90

118.90

118.90

143.90

20%

117.70

117.70

117.70

142.70

30%

116.60

116.60

116.60

141.60

40%

115.40

115.40

115.40

140.40

50%

114.20

114.20

114.20

139.20

60%

113.10

113.10

113.10

138.10

70%

111.90

111.90

111.90

136.90

80%

110.90

110.90

110.90

135.80

90%

109.00

109.00

109.00

134.00

100%

107.20

107.20

107.20

132.20

110%

105.40

105.40

105.40

130.40

120%

103.50

103.50

103.50

128.50

A

(1) Figures for this machine apply to replacement components only.

Fig 8.

11 - 56

9803/3010-4

11 - 56

Section 11 - Service Information Service information Lower Roller Wear Guide (Ital Track)

Lower Roller Wear Guide (Ital Track) Model

JS70

JS130

JS200

0%

110.0

140.0

150.0

10%

109.1

139.3

20%

108.2

25% 30%

JS240

JS300

JS460

154.0

180.0

190.0

148.5

153.2

178.5

187.9

138.5

147.0

152.4

177.1

187.8

107.7

138.2

146.2

152.0

176.4

187.2

107.3

137.8

145.4

151.5

175.6

186.7

40%

106.3

137.1

143.9

150.3

174.1

185.5

50%

105.4

136.3

142.4

149.1

172.7

184.4

60%

104.4

135.6

140.7

147.8

171.1

183.2

70%

103.4

134.8

139.1

146.5

169.5

182.0

75%

102.9

134.4

138.3

145.9

168.7

181.4

80%

102.4

133.9

137.3

144.9

167.8

180.7

Normal Pitch Wear (%)

Dimension A (mm)

101.2

133.0

135.4

142.9

165.9

179.4

100.0

132.0

133.4

141.0

164.0

178.0

110%

98.8

131.0

131.3

139.0

162.0

176.6

120%

97.5

129.9

129.2

136.8

159.9

175.0

A

90% 100%

Fig 9.

11 - 57

9803/3010-4

11 - 57

Section 11 - Service Information Service information Lower Roller Wear Guide (Berco Track)

Lower Roller Wear Guide (Berco Track) Model R3

JS70

JS110(1)

JS150

JS200

JS300

701337

704464

712105

JS130HD

JS330

JS450

JS130 From serial No. XO

699381 JS70

JS130

JS450

JS160-260 Normal Pitch

171.45

175.50

190.00

203.20

Dimension A (mm) Wear (%)

normal impact

normal impact

normal impact

normal impact

0%

140.00

150.00

150.00

180.00

10%

139.20

148.80

148.80

179.20

20%

138.40

147.50

147.50

178.40

30%

137.50

146.30

146.30

177.60

40%

136.50

145.00

145.00

176.80

50%

135.50

143.80

143.80

176.00

60%

134.30

142.20

142.20

175.00

70%

133.00

140.60

140.60

173.80

80%

131.50

139.20

139.20

172.60

90%

129.90

137.60

137.60

171.30

100%

128.00

135.20

135.20

170.00

110%

126.70

133.00

133.00

167.30

120%

125.00

131.00

131.00

164.00

A

(1) Figures for this machine apply to replacement components only.

Fig 10.

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9803/3010-4

11 - 58

Section 11 - Service Information Service information Idler Roller Wear Guide (Ital Track)

Idler Roller Wear Guide (Ital Track) Model

JS70

JS330

JS460

Normal Pitch Wear (%)

Dimension A (mm)

0%

22.0

25.0

25.0

10%

22.4

25.5

25.5

20%

22.8

25.9

25.9

25%

23.0

26.2

26.2

30%

23.2

26.4

26.4

40%

23.7

27.0

27.0

50%

24.1

27.6

27.6

60%

24.6

28.2

28.2

70%

25.2

28.8

28.8

75%

25.5

29.2

29.2

80%

25.8

29.5

29.5

90%

26.4

30.2

30.2

100%

27.0

31.0

31.0

110%

27.7

31.9

31.9

120%

28.5

32.8

32.8

B

Fig 11.

11 - 59

9803/3010-4

11 - 59

Section 11 - Service Information Service information Idler Roller Wear Guide (Berco Track)

Idler Roller Wear Guide (Berco Track) Model R3

JS70

JS110

JS150

JS200

JS300

701337

704464

712105

JS130HD

JS330

JS450

JS130 From serial No. XO

699381 JS70

JS130

JS450

JS160-260 Normal Pitch

171.45

175.50

190.00

203.20

Dimension A (mm) Wear (%)

normal impact

normal impact

normal impact

normal impact

0%

19.50

19.00

21.00

19.00

22.50

22.50

10%

19.80

19.20

21.30

19.40

23.10

22.80

20%

20.10

19.40

21.60

19.80

23.70

23.10

30%

20.40

19.60

21.90

20.20

24.30

23.40

40%

20.70

19.80

22.20

20.60

24.90

23.70

50%

21.00

20.00

22.50

21.00

25.50

24.00

60%

21.30

20.20

22.80

21.40

26.10

24.30

70%

21.60

20.40

23.10

21.80

26.70

24.60

80%

21.90

20.60

23.40

22.20

27.30

24.90

90%

22.20

20.80

23.70

22.60

27.90

25.20

100%

22.50

21.00

24.00

23.00

28.50

25.50

110%

23.25

21.50

24.75

24.00

30.00

26.25

120%

24.00

22.00

25.50

25.00

31.50

27.00

B

Fig 12.

11 - 60

9803/3010-4

11 - 60

Section 11 - Service Information Service information Track Plate Wear Guide (Ital Track)

Track Plate Wear Guide (Ital Track) Model

JZ70

JS460

Normal Pitch Wear (%)

Dimension A (mm)

0%

18.0

26.5

10%

16.8

24.7

20%

15.7

22.9

25%

15.1

22.0

30%

14.5

21.1

40%

13.3

19.3

50%

12.1

17.4

60%

10.9

15.6

70%

9.7

13.7

75%

9.1

12.8

80%

8.5

11.9

90%

7.2

9.9

100%

6.0

8.0

110%

4.7

6.0

120%

3.5

4.1

A

Fig 13.

11 - 61

9803/3010-4

11 - 61

Section 11 - Service Information Service information Track Plate Wear Guide (Berco Track)

Track Plate Wear Guide (Berco Track) Model R3

JS70

JS110

JS150

JS200

JS300

701337

704464

712105

JS130HD

JS330

JS450

JS130 From serial No. XO

699381 JS70

JS130

JS450

JS160-260 Normal Pitch

171.45

175.50

190.00

203.20

Dimension A (mm) Wear (%) 0%

18.00

25.00

25.30

25.50

26.50

30.50

10%

17.00

24.00

24.30

24.00

24.80

29.00

20%

16.00

23.00

23.10

22.50

23.40

27.50

30%

15.00

21.50

21.50

21.00

21.60

26.00

40%

14.00

20.50

20.50

19.50

20.50

25.50

50%

13.00

19.00

19.00

18.00

19.00

23.00

60%

12.00

18.00

18.00

16.50

18.00

21.50

70%

11.00

16.50

16.50

15.00

16.50

20.00

80%

10.00

15.00

15.00

13.50

15.00

18.50

90%

9.00

14.00

14.00

12.00

14.00

17.00

100%

8.00

12.50

12.50

11.00

12.50

15.50

110%

7.00

11.50

11.50

9.00

11.50

14.00

120%

6.00

10.00

10.00

7.50

10.00

12.50

A

Fig 14.

11 - 62

9803/3010-4

11 - 62