Ken964

And I was hoping for something neat like an exploded clutch disk...



This pressure plate has 30k miles on it according to the PO records.

The flywheel is also nicely glazed.




Ken
____________
'89 C4 Coupe

springer3

What brand pressure plate? There is no sign that the spring is scortched, so it appears they missed the target on the heat treating. The only other possibility is the installation was incorrect, and the spring was over-stroke when the clutch was released.

Ken964

It is a Sachs plate. The numbers on the fingers are 147 306 SAX 4 01 and the cast numbers are TYP OMFZ241 Also, the other picture does not really show it but the spring is coming towards you, not away.



Ken
___________
89 C4 Coupe

Ken964

So my clutch woes have finally come to an end. It turns out it was not the master, slave, a loose fitting, or poor bleeding, it was the cracked pressure plate. I put her all back together last weekend and took her for a drive and everything is great - no slipping, no sticking, no grinding.



Ken
______________________
89 silver C-4 Coupe
97 Volvo 960 wagon

Mike Murphy

Based on the glazing, it appears to me that this was caused by excessive heat. Do you suspect that because the spring looks normal that it doesn't look like excessive heat caused this?

springer3

"Based on the glazing, it appears to me that this was caused by excessive heat. Do you suspect that because the spring looks normal that it doesn't look like excessive heat caused this?"

It definately got hot enough to burn off the oil and grease and cause the rust. I think it did not get hot enough to embrittle the steel because there is no evidence of blueing on the spring itself. There may be thermal stresses at temperatures much below the metallurgical limits that caused the crack, so you may be correct, it may have been heat.

Ken964

I did not have symptoms of glazing (slipping) until the end and there was no chatter.

It went something like this:

1. Clutch does not disengage, bleed slave. Normal clutch for about 500 miles
2. Clutch does not disengage, replace slave, bleed clutch. Normal clutch for about 500 miles
3. Clutch does not disengage, replace master, bleed clutch. Normal clutch for about 200 miles
4. Clutch does not disengage, bleed clutch and see how far the pedal will have to travel to disengage clutch, the ring gear engaged first, This is when the slipping started. Normal clutch for about 500 meters.

My thought was that the plate was a little cracked so it could still provide presure but not disengage until the slave was overextended and that it eventually inverted itself during driving and failed to be useful

Ken