Subject: Clutch release
Date: Tuesday, 24 Aug 1999
Organization: Doc's Auto Clinic
To: mohja@gte.net

Hi Jim, Doc here, is your clutch original? It sounds like you are having a pressure plate problem locking up the disc to the flywheel. It is highly likely that the flywheel has hot spots where the metallurgy has changed and the hot spots stop the surface contact from being over the perimeter of the disc surface. The entire assembly must be replaced and if you are keeping the "Z" you may elect to go to an upgrade clutch that is available from several manufacturers. Also please check to see if there is oil, either transmission or engine that could contaminate the disc and cause this situation again.
I hope that this helps you.............

ZDOC OUT

Jim Horn wrote:

Doc: Help. My 91 SR-71 TT has a new problem. After some normal driving in hot weather my clutch will slip badly. Not all the time but oft times. What gives? Does the release sleeve on TT's sometimes stick? I don't drive this car often and thought maybe the release sleeve might be hanging up. Is there a relatively easy check I can try.

Appreciate you.

Jim Horn, Denton, TX

Subject: Clutch release....Follow Up
Date: Sat, 28 Aug 1999 00:59:04 -0700
From: zdoc <zdoc@yosemite.net>
Organization: Doc's Auto Clinic
To: mohja@gte.net

Hi Jim, Doc here, I'm glad to hear that sometimes the simple things are the "Fix" for the situation. I suppose that you know it is very difficult to diagnose problems over the Internet and come up with the answer all the time. Sometimes it is necessary to get another perspective to rethink the situation and then
solve the problem. So many times we must use all our faculties to address the solution, and with a little help from God the answer always comes.

As far as the pedal adjustment is concerned, the rule of thumb is that the push rod must be loose enough for the pivot pin to be rotated that goes through the pedal and clevis. It would appear that the increased temperature caused the clutch fluid to expand more and thereby applying pressure to hold the pressure plate fingers slightly applied to release the disc. Very much like riding the pedal and not letting the disc
completely lock up.

Glad to be of assistance to you...............

ZDOC OUT

Jim Horn wrote:

Doc: Thanks for the clutch comments. Now for my confession and the rest of the story. I failed to do a simple clutch pedal adjustment check prior to emailing you. Thank goodness this was the problem. I do have a high dollar clutch already and was getting ill thinking about it. Have no idea why the adjustment
needed changing as the lock nut was tight, etc. Just thrilled that it's fixed.
Hey, when the outside temp is over 100 for a month who knows what may occur. Sorry to bother you before I did the simple checks. Thanks for all you do for us.

Jim Horn, '91 SR71, Denton, TX