JKelly

I'm in the middle of a clutch job and I see this redish oxide colored stuff (not rust, lubricant maybe) on the pressure plate spines and around the pilot bearing on the flywheel. I've seen this stuff in pictures of clutches posted by other Rennlisters too.
Does anyone know if this is some sort of spray-on dry lubricant or rust inhibitor that was applied at the factory? It appears to be spread in a uniform, sprayed, fashion. The WSM doesn't refer to it at all.
Thanks

Here's a pic:

JKelly

HERE is another pic I found in the 964 forum.

Vilhuer

Isn't there reference to Optimoly TA or such in WSM? Never seen the stuff so no idea what color it is. Seems to be very hard to come by as company was sold to Castrol if I remember right and this stuff discontinued. I have unused twin disk clutch still in Sachs boxes but those parts do not have any clearly visible grease coating. Possible reason might be that release bearing isn't on pressure plate.

Jim M.

I've seen it on other cars when doing clutch jobs. I believe it's clutch dust from the wear of the clutch material.

Jim Mayzurk
93 GTS

Vilhuer

Dust I have seen has been darker in color. Different clutch material could of course be different color also.

WallyP

Looks like iron oxite from fretting wear to me. When you get a steel part that just barely moves, (broken, loose, etc.) you get a very, very fine steel powder that rusts instantly, and spreads thinly all over the area. It could also be mixed with the lube that has been thrown from the splines on the clutch shaft.

Normally, you do not want a coating of lube on the clutch parts...

JKelly

ahhh,, that makes sense Wally. Probably very fine steel powder from the clutch pressure plate surface and the two intermediate plate surfaces. As the plates wear over time, the powder spreads around evenly. I thought it may have been some kind of dry lubricant or something because it felt similar to graphite....it was also on the splines of the clutch disks and central shaft. When I cleaned it off, the surfaces that it was on were in great condition and weren't rusty at all..............thats why I didn't think it was rust.
Cool