Unusual clutch issue (Page 2/8)
Patrick JUL 25, 07:27 PM

quote
Originally posted by stevep914:

...my pedal softens ...the pedal comes back up



When the pedal "softens" (before it "comes back up"), does it actually sit closer to the floor at rest... or does it remain in the same location at rest, but is simply easier to push to the floor?
stevep914 JUL 25, 07:59 PM
I would have to think about that one, I believe the pedal is in the same place as normal; just easier to push. I do remember I know immediately when the problem starts; it is not a slow deterioration. Last shift is good, and then the next one doesn’t happen. I just put the car on jackstands to do another bleed tomorrow, using dot 4. Can’t hurt. I will try it again after that to see if and what that pedal does, if the issue still exists. I am not set totally on the fact this is related to heat from the header, but it IS awfully close to the slave. If we can’t figure out anything else, I would consider wrapping the header in that area. Thanks again for trying to find a solution to this! Steve
fierofool JUL 25, 08:25 PM
I had heat soak on the slave fluid line on a couple of cars. My solution after being sure the system was fully bled, was to slip a piece of split wire loom over the fluid line, push it all the way down to the bottom until it stopped, then cut it off just below the metal tubing of the fluid line. Much easier, faster, and cheaper than header wrap.

If the fluid line will easily unscrew from the bottom of the slave, you might rotate it a little (it has a bend that directs it toward the header) then tighten it to give more clearance.
Patrick JUL 25, 08:49 PM

quote
Originally posted by fierofool:

I had heat soak on the slave fluid line on a couple of cars.



Charlie, when you had this issue, did the pedal suddenly go "soft" and then go back to normal again once it cooled down? Did the fluid levels change? I've never had this issue, so it's difficult for me to understand how "boiling" fluid would affect the clutch in this manner.

I'd be more inclined to think that Steve's problem is some sort of valve issue within the master cylinder.
Spoon JUL 25, 09:07 PM
Your problem sounds heat related. Might as well cut thru the chase, do a complete transfusion and remove all doubt. Go with DOT 5.1

Spoon

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"Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut

stevep914 JUL 26, 12:02 AM
Spoon, I am lucky to find dot 4 in Mexico. No 5 here. I am going to try the dot 4 tomorrow, and see if I can even find header wrap here. I have the line right up to the slave covered in insulation already down to where it curves under the floor. I will let all know, what goes on after I do this. Might take a couple of days. Thanks all. Steve
fierofool JUL 26, 09:08 AM

quote
Originally posted by Patrick:

Charlie, when you had this issue, did the pedal suddenly go "soft" and then go back to normal again once it cooled down? Did the fluid levels change? I've never had this issue, so it's difficult for me to understand how "boiling" fluid would affect the clutch in this manner.

I'd be more inclined to think that Steve's problem is some sort of valve issue within the master cylinder.



When first starting, the clutch would work normally. After a drive of 10 miles or so, the clutch would begin having disengagement problems. Once after a decent drive, I encountered a traffic light. Had it not been for the empty right turn lane, I would have had to rear-end a car. I got stopped in a mall parking lot and did a gravity bleed and returned home. The operation got better as it cooled, but would sometimes require a bleed. I thought I had a leak that was pulling air, so I replaced the slave with a stock unit. It didn't solve the problem.

I think it was on this forum that I learned of the heat problem and found that my fluid line passed very close to the crossover coolant hose. When I loosened and moved the line away from the coolant hose and sleeved it, the problem was solved.

Don't use auto parts store wire loom. It probably won't hold up to engine bay heat. If you can, get nylon wire loom. It should have a silver or gray stripe running the length. Voice of experience.

fierofool JUL 26, 09:11 AM

quote
Originally posted by Spoon:

Your problem sounds heat related. Might as well cut thru the chase, do a complete transfusion and remove all doubt. Go with DOT 5.1

Spoon





I've seen several warnings that the rubber parts in our braking and clutch system aren't compatible with DOT 5. DOT 4 is the max that should be used.

stevep914 JUL 26, 10:07 AM
Upon inspection, my clutch line is right against the crossover coolant pipe, just below where my clutch line insulation stops. I will address this issue along with everything else. Thanks! Steve
stevep914 JUL 26, 03:21 PM
Just to keep all that have helped in the loop: today I think I have eliminated heat as being the source of the problem. All exhaust pipes within proximity of the slave and lines has been wrapped with titanium wrap. Also did the cooling crossover pipe, and the clutch line from the slave down to where it separates from the cooling line under the car. Horrible job, by the way! Hopefully tomorrow I will do a fluid replacement with a bleed, and then see if my efforts, ( and yours) have generated any positive results. It is always good to do projects; while wrapping the exhaust, I found a two inch hole in my one and only muffler. The car has no mufflers other than a single 1 foot long 6 inch wide can shortly after where the exhaust pipes from the headers get together, and two small resonators in the middle rear of the car where they exit. It DOES sound like an exotic. We have no emissions testing here, so anything goes. Steve