Spongy Clutch

[Achilles]

I know I started a thread on this before, but I'm still not satisfied with my clutch operation. I took Whalepirot's advice and had my mechanic bleed the system again this time removing the slave unit. I even took a copy of the proceedure from my Hayne's manual to him as a reference. I just got the car back yesterday, and while it seems better, it still doesn't feel quite right.

The operation of the clutch is very smooth, but all the action takes place near the floor board area. I'd say the last 25-30% of the pedal travel. The first 3/4 or so of depressed pedal does nothing. For those of you with manual trannys, what is the normal pedal location for engagement/disengagement? It seems to me that it should be between the 25-75% area of the pedal movement, if that makes sense. The only thing I can think of is they still aren't bleeding the systen correctly, or they removed too much material when they resurfaced the flywheel. Is there a minimum tolerance for flywheel thickness? I can't imagine that it would make that much of a difference in the action of the clutch pedal. I thought maybe the slave unit went bad, but it seemed fine before the work was done. Any help would be greatly appreciated.

You know what they say...If you want it done right, do it yourself.

 

[WhalePirot]

It seems to me that it should be between the 25-75% area of the pedal movement.

That's where mine 'operates', even with the HP aftermarket clutch. At 25% of pedal, my car's clutch is starting to release; at roughly 70% of pedal, the clutch is disengaged

Either they didn't follow the procedure, in which the tilting of the unit while bleeding is imperative, or one suffers your car's symptoms, or there is a problem with your clutch master or slave.

 

[vigman]

I assume this is the 95 were talking about

Read this post....... All of it..
http://www.corvetteactioncenter.com/forums/showthread.php?t=17210&highlight=Clutch+slave

Good luck..
Vig~

 

[WhalePirot]

A true enthusiast's board

Great post, Vig!

I change my brake and clutch fluids when they get dark, indicating water absorption. Even in this dry climate, I hardly go more than a year.

The 'lower' DOT numbers reflect, among other things, less heat tolerance, before boiling. Silicone fluid does not absorb water, but yields a spongy feel and is probably too expensive to justify for most streetable cars.

This bleed job is not at all difficult. I thought that 45 degrees of rotation was called for but my manual is quite far away. The slave is easily removed, as is the rod. It might be a useful skill for those who change their own oil and such.

Also, the specified spin-down time for reverse engagement on the 4+3 is about 9 seconds, I believe. That is not after choosing a forward gear, which is a backup (not routine) procedure. If you have to do this before selecting reverse, you are in for clutch work soon. You may also be facing early tranny work, as the clutch is not fully performing its role of unloading the synchros during a shift.

 

[vigman]

It's just the way I do it

It seems to work....

9 seconds for the tranny to spin down WOW.. that's a LOT of internal inertia.. or some great bearings and thin oil.....

Vig~

 

[Achilles]

Thanks Vig & WhalePirot for the reply. It's just as I thought, that the clutch still isn't right. I should take it back to the shop again, but I think this time I will try to muddle my way through it myself. I should learn this stuff anyway. My tranny now grinds when I put it in reverse and it never did that before. My mechanic also told me to put it in 1st gear before selecting rev. I think that was his way of covering his A#@ for not doing the job right.

BTW I'm still a little unclear as to what fluid to use. Is Dot 3 not good?

And, what about Royal Purple synthetic fluid?

Also, this car is a 1986 4+3.

Thanks again guys.

 

[Achilles]

BTW Vig, I will be sure and follow the system bleed procedure in the other thread.

Thanks for the info.