Slave cylinder Woes

I have been through my second one (wilwood) in 1000 miles. I have a 351 W. mated to a Tremec 5 speed. Slave is mounted to the bellhosing and attaches to stock mustang clutch arm. They eventually start to leak and then go out. Any ideas. Is there a certain way to set them up?

Curt,
I have the same setup on my car and so far no problem. Could be your master cyl is too large and is forcing too much fluid thru your slave.
Both should be the same size.
My best guess,
RACER X #99

Curt,

How well does the slave line up with the fork? A little off-center force could be wearing out the seals prematurely. Also, make sure that you're not getting any water in the system from somewhere.

Bob P. -ERA-

Curt,

As Bob and Racer X state, cylinder size and angle definitely come into play. If you have a 3/4" reservoir, you need a 3/4" slave.

I haven't heard any problems with the Wilwood cylinder. I know the stock Girling cylinder doesn't have a retaining spring and sometimes the wrong angle or too much pressure blow it out.

I had some other Cobra folks tell me about the CNC Slave cylinder. It is supposed to work great. It has the proper retaining spring and never fails.

John

[This message has been edited by John McMahon (edited 11-30-1999).]

We use strictly Wilwood and Tilton in our cars - we have found the problem to be: Silicone Fluid. They should come with a warning & Wildwood stated they would put it in their new installation guides. The seals will soften and leak if silicone is used.
Could be an alignment problem - or is it Silicone?

[aumoore]

I have about 1000 miles on my Wilwood pull type slave cylinder and it has developed a leak. Has anyone rebuilt one of these puppies and did you buy teh rebuild kit or just get new rubber o-rings from a industrial supply shop?

I spent a lot of time making sure there was no side loading on the cylinder and I am using DOT 3 brake fluid(not silicone)

Thanks

[Mr.Fixit]

I think that the puller type slave cylinders are more prone to leaking because the rod is attached to the piston directly, without a pivot at the piston / rod interface. Pusher slaves allow the pushrod to pivot at the contact point at the piston, so the piston does not get sideloaded so heavily I never installed puller slaves by choice, they're more expensive and seem to not be as long lasting. A homemade bracket cut out of 1/4" thick mild steel 90 degree angle iron can be bolted to the tranny / bellhousing bolts on the driver's side and attach any pusher slave you like. Make the pushrod out of a 7/16" bolt that you cut to length and round both ends on. Go to NAPA and have the parts guy get out the book, pick a slave with the proper diam. and length for your master cyl and fork throw-distance requirements. This is the setup I preferred, tried a few different slaves over the years, depending on master cyl being used at the time.