Clutch problems

My McLeod internal slave cylinder started to leak so I installed new seals thinking this would solve my clutch hydraulic failure. No more leaks, good pedal for about 20 strokes, but then goes totally soft. Have bled the system several times. Master fluid reservoir never goes down (except when bleeding) and no fluid leaks anywhere. I'm thinking air leak with master cylinder seals? Don't know why this happened concurrently with the slave failure? Any advice before I dig into the front end on the SPF?

Sounds to me fluid is bypassing the seals, either in the master, or in the hydraulic throwout bearing. Given that you were just futzing with the latter, that's where I'd cast my initial suspicions.

I just had a McLeod unit overhauled by them a few weeks ago. They changed the bearing and fitted new seals and turned it right around to me, free of charge. This is after the seals failed after 18 years of use!

If your clutch initial works, then doesn't, that doesn't really sound like air in the lines to me, although I could be wrong. Are you pressure-bleeding the system, or vacuum-bleeding, or old-school down-up with the pedal?

And at the risk of insulting your intelligence, I have to ask, are you sure you are bleeding the unit properly?

Mike,
I'm bleeding old school with pedal up and down, shutting the bleed line on a down stroke. Probably 30 strokes at each bleeding. I get a fair amount of air out bleeding. After bleeding the pedal is initially hard, but softens progressively until no pressure after 25 strokes. Interestingly the fluid reservoir doesn't go down with the softening and no fluid leaks anywhere. I've repeated the bleeding at least 10 times, but same result. Can't understand where the air is coming from. I've had my SPF for about 2 1/2 years and this started 2 months ago.

Dave,
I too had bad seals in the McLeod slave cylinder, which they rebuilt for me also. Then, I had a complete loss of pedal pressure later which turned out to be the master cylinder. The symptoms you are having are identical to mine. I replaced the master cylinder...problem solved! In the process, I have always had a very stiff pedal pressure for the clutch since new. It turned out that the master that was installed by the factory was not the correct size. The replacement from superformance with a smaller size piston gave me a much more normal pedal pressure.
The car had about 10k miles on it when these problems came up.
Have had the car about 2 1/2 yrs. +

I have similar symptoms. Mine stars out soft...then becomes hard after some vigorous strokes...then after that same 25 strokes it becomes soft again. My mechanic (wife) is very disappointed with this performance and believes something needs replacement....

tom c said:

Dave,
I too had bad seals in the McLeod slave cylinder, which they rebuilt for me also. Then, I had a complete loss of pedal pressure later which turned out to be the master cylinder. The symptoms you are having are identical to mine. I replaced the master cylinder...problem solved! In the process, I have always had a very stiff pedal pressure for the clutch since new. It turned out that the master that was installed by the factory was not the correct size. The replacement from superformance with a smaller size piston gave me a much more normal pedal pressure.
The car had about 10k miles on it when these problems came up.
Have had the car about 2 1/2 yrs. +

Click to expand...

Thanks for the reply. I finally did get some leakage from the slave cylinder again. Removed it and sent it to McLeod. It appears to leak from the swivel fitting at the feed line. McLeod's seal design doesn't look as good as Tilton with integral AN fittings, but I don't think it would be easy to fit a Tilton slave cylinder since they bolt to the bellhousing. I sure hope this isn't a recurring problem. This fails again and I'm looking at an external slave set up.

Cliffbeer2 said:

I have similar symptoms. Mine stars out soft...then becomes hard after some vigorous strokes...then after that same 25 strokes it becomes soft again. My mechanic (wife) is very disappointed with this performance and believes something needs replacement....

Click to expand...

It could be worse Cliff. I can barely remember the last time mine got fully engaged.