[DeTomaso] Clutch problem solved?

[tmshinro at aol.com]

 I want to thank everyone that sent suggestions/ideas on how to resolve my clutch drag.    I think I have the problem resolved so I thought I post what I did for those of you who are interested.

The comment that turned on a light bulb for me came from John Taphorn (thanks John).  He had mentioned that sometimes the needle bearings supporting the shaft that the clutch lever attaches to become worn and produce some fore/aft movement of the shaft that consumes the initial movement of the slave pushrod and results in less than the full stroke working on the clutch lever.  He mentioned that with the marginal system, even a small loss of movement from the pushrod can make a big difference.   When I read that, I realized that what I thought was insignificant may be my problem.

That problem was that the new slave I got did not fit snugly into the hole in the holding bracket and the two retaining clips on the top and bottom of the slave did not totally secure the slave cylinder into the holding bracket.   I'm not talking a lot of movement, but it was readily visible that the initial stroke of the pushrod resulted in the slave cylinder moving upward in the holder a tiny bit until the bottom clip was against the holding bracket.  Only after the cylinder was braced against the bracket did the pushrod start acting on the clutch lever.  I figured this might be the missing "throw" that I needed.

I ended up filing down the thickness (0.050" to 0.030") and boring out another retaining clip to act as a spacer in the gap between the bottom clip and the holding bracket.   With the spacer between the bottom clip and the bottom of the holding bracket, the cylinder was forced down in the holding bracket (thereby lengthening the stroke a small amount) until the top clip was flush with the top of the holding bracket.   All the slop was removed so the initial movement of the pushrod immediately started pushing the clutch lever.   

I also had to reduced my free play to the absolute minimum.   The result was that I have a hot measurement of 0.022" of clearance between the clutch disk and the pressure plate after extended drives and have no clutch drag.   I'm still curious why I can't get the stock clearance of 0.030" but then again, I don't know if I ever had it to start with.   The car drives and shifts great.

Since I replaced the MC and slave, my clutch feels much lighter than it had before.   My clutch was always real heavy with the old MC and slave (remember 15 year old seals enduring humid midwest summers and long winter storage periods).   I haven't tried any aggressive attempts to bleed my clutch (again) but wondered if the soft pedal could be the result of air in the line?  Right now, I'm kind of enjoying the lighter clutch with a car that drives well, so I'm not inclined to mess with it.  

Thanks to all again,
Tom
#5186