DRIVE SHAFT REMOVAL & INSPECTION STRUCTURE
Objectives Dismounting Dismantling and Inspection Assignments Class Assignment Home Assignment Summing Up Possible Answers to Self-check Questions Terminal Questions References Glossary
DRIVE SHAFT REMOVAL AND INSPECTION
In the Maruti car, which is a front wheel drive car, power is transmitted from the differential to the front wheels through two drive shafts. Drive shafts can transmit power at an angle and can also change their length. This is possible because a drive shaft has two constant velocity joints – one at each end. Thus, the drive shafts and the constant velocity joints together perform the function of the propeller shaft, the universal joints, and the sliding joint of the power train in the conventional layout. The constant velocity joint is composed of an outer race, a cage, an inner race and balls. During rotation, the six balls lock the outer race and the inner race completely and transmit drive even at an angle. The shaft is also capable of movements in the axial direction through the balls, which can slide in the grooves of the outer race.
Objectives i. ii.
After going through this lesson you will be able to: Remove the drive shaft from the car Dismantle the drive shaft
Dismounting The following steps should first be completed on both the front wheels, one wheel at a time.
Remove the wheel cap from the front wheel. Remove the split pin from the front axle nut and loosen the castle nut with a No 30 ring spanner. Remove the castle nut and the washer. Loosen the front wheel nuts of both the wheels with a wheel spanner. Jack up the car with a hydraulic garage jack at the front. Next, the following steps should be completed on both the front wheels.
Unscrew the wheel nuts from the wheel. Remove the wheel. Place a safety stand under the body of the car. Release the hydraulic pressure of the jack and remove the jack carefully. Drain the transmission oil by removing the drain plug with the help of an allen key and collect the oil in a tray. Screw in the drain plug and wipe the area with a waste cloth.
Draw the drive shaft out of the snap ring fitted on the splines of the differential side gear. The drive shaft cannot be taken out from the side gear yet.
Draw the other drive shaft out of the snap ring fitted on the splines of the differential side gear. Remove the four bolts holding the two stabilizer bar brackets with a No 14 socket and ratchet handle. The stabilizer bar brackets are fitted on the front cross-member.
Remove the split pin from the tie-rod end castle nut and loosen the nut with a No 17 ring spanner. Unscrew the nut. Remove the tie-rod end from the steering knuckle with the help of the tie-rod end remover. Remove the tie-rod end on the other side similarly. Unscrew the bolt holding the front suspension arm ball stud with a No 14 socket and handle. Remove the front suspension arm ball stud from the knuckle with the help of a lever or by striking it lightly with a hammer. Strike the axle with a plastic hammer and remove the drive shaft from the wheel hub. A plastic hammer is used so that the face of the axle does not get damaged.
Screw in the nut and hit on the face of the nut.
Similarly, the bolt is unscrewed and the front suspension arm ball stud is removed on the other side. The drive shaft on the other side is removed in a similar manner. All the parts should be washed thoroughly and dried by blowing air over them before assembly. The rubber boots should never be washed with petrol, kerosene, or any other de-greaser and the boots should always be wiped only with a clean cloth.
Fig. 9.1: Drive shafts with CV joints.
Self-check Questions 1. In the Maruti car, power is transmitted from the differential to the front wheels through ___________. 2. Drive shaft can transmit power at _________and can also ___________ its length. 3. How many constant velocity joints does each drive shaft have? 4. The constant velocity joint is composed of how many components? Name them. 5. In order to remove the drive shaft from the car we have to remove it _____________________________________and the _______________.
Dismantling and Inspection A quick visual inspection is made to check the boots, etc. and if a crack is detected, they should be replaced.
Remove the larger boot band with the help of a screwdriver and remove the boot from the differential side constant velocity joint. Remove the smaller boot band and slide the boot on the shaft away from the constant velocity joint. Remove the snap ring and pull out the shaft along with the bearing cage and balls from the outer race.
Fig. 9.2: Boot.
The outer race has six grooves for the six balls of the bearing.
Outer Race Grooves
Fig. 9.3: (a) Bearing cage. (b) Circlip.
Remove the circlip at the end of the shaft with a circlip plier and remove the bearing cage. The bearing cage and circlip are shown in the figure.
The splines, on which the inner race is mounted, should not be worn. The journal which carries the oil seal on the differential side should be smooth and shiny.
Check the differential side constant velocity joint outer race internal grooves for wear. Check the oil seal journal and the internal splines for wear. Check the balls and the bearing cage for wear. Check the shaft splines and lock groove for wear. Check the circlips, snap ring, and boot bands for wear or damage. If any part is found to be worn or damaged, it should be replaced.
Check the rubber boot for deterioration and cracks and even if a minor crack is detected, the boot should be replaced with a new one.
Check the constant velocity joint on the wheel side, shown in the figure, for wear by holding the shaft and the axle in hand and then pulling and pushing.
The standard axial play in the constant velocity joint on the wheel side is 0 mm, that is, there should be no play. If the wear is beyond the permissible service limit of 1.5 mm, the drive shaft assembly should be replaced because no repair is recommended on the wheel side constant velocity joint.
Splines
Axle Spindle Threads
Oil Seal Journal
Fig. 9.4: Wheel side constant velocity joint.
Check that the oil seal journal, the splines, and the axle spindle threads are not damaged.
Self-check Questions 6. The outer race has six ________ for the six _________of the bearing. 7. Both side CV joints are similar in construction. State whether True/False 8. Axial play in the constant velocity joint on the wheel side should not be more than _________. 9. The whole drive shaft assembly should be replaced if the axial play in the constant velocity joint on the wheel side is more than1.5 mm. State whether True/False. 10. The CV joint on the differential side can be repaired. State whether True/False.
Assignments Class Assignment 1. Compare the drive shafts of the front wheel drive with propeller shaft of rear wheel drive car. Home Assignment 1. Write down how the drive shafts manage to transfer power to the wheels even at an angle while steering the wheels?
Summing Up In this lesson we have studied about the functioning, removal and dismantling of drive shafts. Drive shafts can transmit power at an angle and can also change their length. This is made possible by the constant velocity joints – one at each end. Both the CV joints are different from each other in construction and working. Now in the next lesson we will assemble and re-mount the drive shaft and CV joints in the car.
Possible Answers to Self-check Questions 1. 2. 3. 4. 5.
two drive shafts an angle, change two an outer race, a cage, an inner race and balls out of the snap ring fitted on the splines of the differential side gear, wheel hub 6. grooves, balls 7. False 8. 1.5 mm 9. True 10. True
Terminal Questions 1. Compare the 2 types of CV joints.
References 1. Maruti 800 Service Manual
Glossary Boot
Rubber piece with folds used as a covering against dust etc.
Circlip
Spring locating or retaining clip; can be lifted on to a spindle (in an external groove) or in a bore (in an internal groove). Circlips are used in some pistons to locate and secure the gudgeon pin.
Constant velocity joint
Two closely coupled universal joints arranged in such a way that their acceleration-deceleration effects cancel out. This results in an output shaft speed identical with input shaft speed, regardless of the angle of drive
Conventional layout
Front engine driving the rear wheels
Drive shaft
Alternative term for the half-shafts. Usually applied where the shaft is not enclosed in an axle casing.
Front wheel drive
Vehicle having its drive wheels located on the front axle.
Snap ring
Steel wire split ring inserted in a groove and used as a lock ring
Split pin
Piece of metal of semicircular section bent into the shape of a keyhole with the flat faces lying close together. It is used to lock nuts or other components on to a shaft; the shank is passed through aligning holes or slots and the ends are then splayed.
Stabilizer bar
Anti-roll bar joining the two control arms
Steering knuckle
The inner portion of the spindle that pivots on the kingpin or ball joints.
Suspension arm
Metal part joining the front suspension strut and the body of the car
Tie-rod
A rod that connects the steering arms.
Tie-rod end
Ball and socket joints at the end of tie rods
DRIVE SHAFT ASSEMBLY AND MOUNTING
In the previous lesson we studied that in a Maruti car, which is a front wheel drive car, power is transmitted from the differential to the front wheels through two drive shafts. Drive shafts can transmit power at an angle and can also change their length. We also studied about the removal and dismantling of the drive shafts. In this lesson we will learn about the assembly and mounting of the drive shafts.
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Objectives
After going through this lesson you will be able to: i. Assemble the drive shaft ii. Mount the drive shaft
Assembly After the drive shafts have been inspected and parts that require replacement have been arranged we now re-assemble them.
Apply special constant velocity joint grease in the wheel side constant velocity joint and mount the rubber boot on the joint.
This grease, as per the specifications should be Servo Grease Molex, which is also known as constant velocity joint grease.
Install the band over the boot properly. Install the smaller band in a similar manner on the other end of the boot after fitting the smaller side of the boot in the groove in the drive shaft.
The wheel side constant velocity joint is ready at this stage and the constant velocity joint on the other side is assembled next.
Insert the small band and the rubber boot over the drive shaft. Insert the inner race with the cage and balls on the drive shaft. Install the cage directing the smaller diameter side towards the shaft end. Fix the circlip in the groove on the shaft with a circlip plier. Apply grease on the balls and cage and then slide the outer race over the balls. Fix the snap ring in the groove in the outer race, taking care to see that the open end of the ring is not lined up with a ball. Apply grease to the inside of the outer race.
Slide the boot and the bigger band on the outer race and fix the band. Fix the smaller band on the boot after fitting the boot in the groove in the drive shaft, while ensuring that the boot is not distorted. Insert a screwdriver into the boot on the outer race side and allow air to enter the boot so that pressure in the boot is the same as atmospheric pressure. The other drive shaft is assembled in a like manner.
Mounting For mounting the two drive shafts in the car, the car should be in the raised position on two safety stands as it was left after dismounting the drive shafts. The right hand side drive shaft is fixed first.
Insert the differential side constant velocity joint in the transmission. Hold the bearing outer race of the constant velocity joint and push it over the side gear splines. Apply grease on the splines of the drive shaft spindle and fit the wheel side spindle in the hub. Push the drive shaft from inside so that it projects out from the hub.
The wheel hub is driven by the drive shaft and has the wheel mounted on it and fixed by four nuts.
Smear some grease on the front suspension arm ball joint stud and push it in the steering knuckle hole on the lower side. Tighten the bolt of the front suspension arm ball joint stud with a No 14 socket and ratchet handle. Fit the tie-rod end in the steering knuckle and tighten the castle nut with a No 17 ring spanner. Insert a split pin and bend it properly to lock the castle nut. Place a washer and tighten the spindle nut with a No. 30 ring spanner. The left hand side drive shaft is fitted next.
Insert the left hand side drive shaft on the differential side gear splines by pushing it with hand pressure. Smear some grease on the spindle and insert it in the wheel hub. Insert the front suspension arm ball joint stud in the steering knuckle hole after applying some grease on it for easy fitting. Hit it with a hammer to push it in. Tighten the No 14 bolt to hold the ball joint stud in position. Insert the tie rod end in the steering knuckle. Screw in the castle nut and tighten it with a No 17 ring spanner. Place a split pin in the castle nut and bend it with pliers. Place the washer on the wheel spindle, screw in the nut and tighten it with a No 30 ring spanner.
Fit the stabilizer bar brackets on the front cross member with No 14 bolts. Fit the wheel on wheel hub with four nuts of 19 mm size with a wheel spanner. The other wheel on the opposite side is fitted in the same manner.
Lift the front end of the car with a hydraulic garage jack and remove both the safety stands. Lower the car slowly by loosening the hydraulic pressure release screw. Tighten the wheel nuts fully as per the specified torque. Tighten the axle nuts with a No 30 ring spanner to the specified torque. Insert a split pin in axle hole and bend it properly with pliers. Place the hubcap in place. The same set of operations is also performed on the other wheel.
Remove the transmission cap and fill gear oil EP 90 to the upper mark on the dipstick. Replace the filler cap properly.
During assembly, all nuts and bolts should finally be tightened to the values of torque specified in the table shown below: S. No. 1. 2. 3. 4. 5.
Table 10.1: Tightening torques Bolt or Nut Stabilizer bar mount bracket bolts Ball joint stud bolt Drive shaft nut Wheel nuts Tie-rod end castle nut
Tightening Torque 3.0 to 5.5 mkg 4.0 to 6.5 mkg 15.0 to 27.0 mkg 4.0 to 7.0 mkg 3.0 to 5.5 mkg
Self-check Questions 1. The rubber boots should be washed with petrol/kerosene to clean them. State whether True/False. 2. Grease applied in constant velocity joints is ____________________. 3. How is pressure inside the boot made the same as atmospheric? 4. Which side of the drive shaft is inserted first? 5. Which oil is filled in the transmission?
Summing Up In this lesson, we studied the procedure of assembling and mounting the drive shafts in the car. This brings us to the end of the section on the power train system. In the next course we will study the Electrical systems of a car.
Possible Answers to Self-check Questions 1. False 2. Servo Grease Molex (also known as constant velocity joint grease) 3. By inserting a screwdriver in the boot on the outer race side and allowing air to enter the boot 4. differential side constant velocity joint of the drive shaft is first inserted in the transmission 5. gear oil EP 90
Terminal Questions 1. Describe the assembling and mounting procedure of drive shafts.
References 1. Maruti 800 Service Manual