I'm in the long process (for me at least) of replacing the clutch on my 89 C4.
A quick question, does anyone know what the minimum thicknesses are for the flywheel, pressure plate and friction disc?
Requisite photos to follow as soon as they're uploaded....

 

Clutch disk wear limits
minimum thickness is 0.3 mm - measured between the top of the friction material and the rivet faces.
Lateral runout - 0.6mm

 

wow.
0.3 is mighty thin. (A little under four copier pages thick.)
Amazing.

 

for the friction disc and probably the pressure plate, just replace them. If you did all the work to get the trans out, the parts are cheap enough. As long as the clutch disc did not wear down to the rivets, then the flywheel is probably good.

 

Took some photos of the bits. The clutch friction material measures out at 8 mm from side to side. There is some scoring on the PP and flywheel. Might be from the leaking input shaft seal and tranny fluid all over the inside of the bell housing. (picture not attached - it's just too ugly)

Another thought, is it possible for the PP springs to weaken over time and not provide the same level of clamping force? This has to be the heaviest PP I've ever seen BTW.

(And if this is the original clutch, the friction material and rubber center look remarkable for 230K!)

 

Finally received the new clutch disc today and it doesn't look significantly thicker than the original one. If the old one is 8 mm the new one isn't any more than 10 mm thick. OTOH, the new pressure plate looks like it sticks out further past the mounting posts that fit into the flywheel so maybe the old flywheel is just tired...

Another quick question, how do I get the starter ring off the old pressure plate! It seems almost welded on there and the new pressure plate of course doesn't have the starter ring.

frank

(Colin, yes the parts are cheap enough but the 89 clutch costs twice as much as the 90+ kit )

 

Quick question:
should I get the flywheel ground down a bit? Looking at the flywheel pic above the two dark spots at 9 o'clock and about 2:30 are lower than the rest of the flywheel material, but not visibly so - only when I run my finger across the surface I can feel a slight dip.

Oh, and the starter ring did come off easily once I got it loosened! Just needed to take that deep breath before whacking it...