Clutch rebuilds

[C M Smith <cmsmith@domain.elided>]

I too have replaced only the friction disc when doing a clutch job. In 
retrospect, I should also have renewed the release bearing given the modest 
cost of this. Although, towards the end of the car's life a new disc will 
last longer than the mileage left in the car so no sense spending the money 
on the whole clutch. Input shaft pilot bearing (lodged in the flywheel) 
should be carefully examined and renewed as needed also. As another poster 
also pointed out, always check the input shaft bearing and seal in the 
transmission while it's out too.

The problem with not renewing the pressure plate assembly is not a balance 
problem (the friction disc needs to be separately balanced from the entire 
pressure plate assembly anyway) but a thermal stress problem. The diaphragm 
spring almost universally used these days might last for two full friction 
discs, but then again it might not. Often the pressure plate spring will 
hold tight for the entire second disc service life, often it fatigues and 
won't hold for the last quarter or so of disc life. Occasionally, the 
spring fails shortly after the friction disc is renewed.

Then there's the issue of pressure plate and flywheel wear and tear. Often 
the flywheel needs skimming after the second clutch is done. Pressure 
plates also tend to show stress and wear eventually.

Bottom line is "who's doing the labour?" If you're paying the pro's then it 
makes sense to renew the whole thing every time the disc wears out. If you 
are doing it yourself, or renewing the friction disc before it wears out, 
such as a rear main seal or tranny repair, thenoften it makes economic 
sense to just renew the disc (and release bearing)

There is no hard and fast rule, it depends on your situation. Pressure 
plates tend to be expensive relative to the disc alone.
Michael Smith
Calgary, Alberta
Canada
91 Alfa 164L, White, original owner

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