Clutching at training With clutches and their ancillaries evolving continually, Rob Marshall finds that technicians should embrace training to keep up, at least Tearing the car back down again to investigate why a new clutch is not working as it should is not only frustrating for the technician but it also destroys the job's profitability. While problems with parts can occur, the main causes tend to be damage, or incorrect fitting. Consider, therefore, that a day spent away from the workshop on clutch training can be recouped very quickly.
The pandemic has hit face-to-face training but not killed it completely. Meanwhile, a plethora of technical information and training opportunities are being made available by OE quality suppliers.
The times, they are a'changing Blue Print reminds us that clutch changes take longer now than on cars of the past and it can understand why some workshops do not wish to concentrate on such time-consuming jobs. Aisin, a leader in the Asian vehicle clutch market but with its eyes focussed firmly on European expansion, adds that a further reason is the new trend of increased complication, especially with the growing number of specific tools. Asin Europe reminds us that clutch changes are in the top three revenue product lines for garages but technical expertise is necessary to complete the task correctly, a point echoed by Schaeffler that the complexity of the task also means that many adjacent components have to be removed before the gearbox can even be accessed. Valeo concludes that this is why training is key to tackling clutch replacement and gives technicians and garage owners the confidence to justify the invoice value.
Making knowledge work Taking advantage of regular training pays dividends, especially as it updates technicians on how and why clutches (including their operating systems) are evolving. ZF Aftermarket's ZF [pro] Tech training, for example, includes details about the antivibration assembly, fitted to the hydraulic lines of a variety of models. Incidentally, the engine and clutch characteristics can cause the slave cylinder to resonate and the steel plates within the anti-vibration assembly distort in order to reduce (or stop) pulses being felt through the clutch pedal.
While this explains ZF's reasoning for insisting that you employ either gravity, or low-pressure bleeding methods, bleeding all of the old hydraulic fluid from the system with the old CSC in place is a prudent move. This advantage is that the new cylinder does not have either old, or contaminated, fluid passing through it that risks damaging the seals. Courses tend to cover not just the clutch but also the Dual Mass Flywheel (DMF).
"While technical views and advice differ even between quality OE clutch suppliers about whether dual mass flywheel conversion kits are harmful, or not, at least you will be armed with the appropriate facts so you can build an informed opinion."
CLUTCHES
Knowing about anti-vibration valves is certainly useful but ZF's Technical Training emphasises that not appreciating how and why torque-limiting valves work can be disastrous and embarrassing for the technician. They are fitted to many popular diesel cars and prevent Dual Mass Flywheel (DMF) damage – although you should note that they are often not replaced if they go faulty, thus emphasising the importance of checking the DMF for condition. In any case, torque-limiting
valves work by reducing the fluid flow back to the master cylinder, as the clutch pedal is released. Sachs says that, should a technician be unaware of this, there is a risk that pumping the clutch pedal quickly and repeatedly during the bleeding procedure can introduce excessive fluid into the slave cylinder, which over-extends its piston, which risks tearing the seal lip. Rectifying the issue may mean that the technician has to dismount the gearbox again to replace the concentric slave cylinder (CSC).
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