The most important part of any clutch system repair begins with the initial diagnosis. The primary cause of complaint must be identified correctly, along with any secondary or related concerns, prior to replacing or repairing any components. For example: a clutch might be slipping because it is old and excessively worn, but this phenomenon may also occur for many other reasons (such as grease or oil contamination, release mechanism problems, driver error/abuse, or an incorrect flywheel profile). If the initial diagnosis is not correct, then, despite repair work having been carried out, the vehicle will still be in a state of disrepair. The inevitable consequence of which is usually the premature failure of the replacement clutch.
As with most things in life, prevention is better than cure, so here are the top three installation errors we encounter, along with sure fire ways to avoid them:
The application of excess spline hub grease, or an incorrect grade of grease during installation
This is a very easy mistake to make, which can result in contamination of the friction surfaces, leading to the clutch slipping and/or juddering. Simply apply a small amount of suitable high melting point spline grease to the input shaft, the splined hub, the fork (where it contacts with the releaser) and the fork pivot surface. Then slide the friction disc onto the input shaft, remove and wipe off any excess grease before installation.
Misalignment of the engine and transmission
This can occur for various reasons, including: hanging the gearbox during installation; forcing the gearbox input shaft during installation; a worn or missing pilot bush (spigot bearing); warping of an alloy gearbox bell-housing; damaged or missing gearbox dowel pins; interference between the gearbox and engine mating surfaces caused by dirt or grease accumulation, metal chips, or even by wiring and pipework clips.
To avoid this, it is important to degrease and inspect the gearbox bell-housing thoroughly, ensure a transmission jack is used correctly, and use the relevant clutch alignment tool during installation.
Releaser installation and associated release mechanism faults
It can be very easy to overlook installation errors or incorrectly assume that there are no problems present in this area. Thoroughly inspect the gearbox bearing guide tube, the fork or lever and the cable or hydraulics system for any wear or visible faults. Always follow vehicle manufacturers' recommendations when adjusting or replacing the bearing, the cable or any hydraulics components. Check for any clutch travel adjustment required upon clutch replacement. This may be necessary dependent on the vehicle.
If you encounter a problem or are unsure about something, seek advice before proceeding. You can contact EXEDY Clutch Europe Ltd. via email@example.com or call +44 192 857 1850.
Author: Chris Riley (Technical Department)