Pull Clutch Slave Cylinder chg out

mkassab · #1 (**permalink**) 12-24-2010, 06:55 AM

I've heard of many issues with the clutch slave cylinders on our Cobras, e.g., leaking, wearing out prematurely, breaking. My car only has a few hundred miles on it and already the slave cylinder has drops of brake fluid. One guy I talked to is giving up and going to a cable setup. I've read all the past threads and mind is misaligned also (note the picts of the original slave). Since my problems are starting early with a push type clutch slave cylinder, I changed to a Wilwood "pull" type. I see advantages to this....The good thing about the Wilwood, it has two swivel/pivot bearings, one on each end for a 360 deg of movement, and if mounted correctly, the slave cylinder is always in a straight line, therefore, no side pressure on the cylinder walls. Key benefit.... because its pulling, vs. pushing, it’s easy to keep itself in a straight line (like pulling a rope vs pushing one). I designed a bracket to attach to the frame. Yes, I'm aware of the engine movement/rotation relative to the frame, but it's a very small amount and the Wilwood is designed to handle it with the two pivot points. I'm good to go with the stud through the clutch arm hole relative to free motion. I also "rounded" out the far side of the clutch arm hole where the half-round bushing pivots with a round/ball type grinding wheel via my air grinder... then applied a small amount of wheel bearing grease. I then installed a few fittings and a 7" ss braided hose to connect to the steel line and bleed the master/slave with new brake fluid. While I was in the area, I also install heat shields to my brake and clutch lines that were close to the headers.

Should be good to go now... Mark

mkassab · #2 (**permalink**) 12-24-2010, 06:58 AM

And more pictures:

tcrist · #3 (**permalink**) 12-24-2010, 10:57 AM

I would say as you know that it is not inline, you might want to either shim it or fab up a new bracket to straighten it out. You are already at quite an angle and pressing on the loud pedal will only make that angle worse.

Looks like a very clean design though.

BTW, I have a pull cable setup on my T5. The pivot ball is on the other side of the bell housing so it pulls from the front. I really do not care for it because there is really no adjustment for how much it throws and am thinking about changing to a master and slave with the slave pushing from the rear. There is a slave that bolts right to the ears on the transmission.

mdross1 · #4 (**permalink**) 12-24-2010, 11:02 AM

Our Co had a lot of trucks with hyd clutches giving the techs a real pain trying to keep them working correctly.As I remember It was mostly getting them bled so they were not spongy.

mkassab · #5 (**permalink**) 12-24-2010, 01:00 PM

Quote:

Originally Posted by tcrist

I would say as you know that it is not inline, you might want to either shim it or fab up a new bracket to straighten it out. You are already at quite an angle and pressing on the loud pedal will only make that angle worse.

It's just the picture. The cylinder is at a right angle to the clutch arm.... just as it should be. The the arm only moves about 1/2".... so really no change to the angle.

mkassab · #6 (**permalink**) 12-24-2010, 01:03 PM

Quote:

Originally Posted by mdross1

Our Co had a lot of trucks with hyd clutches giving the techs a real pain trying to keep them working correctly.As I remember It was mostly getting them bled so they were not spongy.

Time will tell, but bleeding the system is very easy using a pressurized system, line Motive bleeder. Also, the Wilwood cylinder has a easy to rebuild kit for ~$18.
Mark

Rick Parker · #7 (**permalink**) 12-24-2010, 06:25 PM

Whether you push or pull the clutch lever, if the direction of travel is not in line with the centerline of the slave it will create side load on the piston and wear a pattern in the bore of the cylinder preventing the rubber seal from doing its job (retaining the fluid under pressure). The applications that work are typically well engineered.