Non-releasing clutch issue

[Reaper1]

OK, I've read a few threads on this issue and have done some of the things suggested in those threads, however I want to get some feedback on my unique case.

It seems over time(since around March this year) that my clutch has gone from wonderful to "won't release at all" when the pedal is fully depressed. I started noticing it when I would try to shift very fast to 2nd gear and would sometimes get clashing. I always thought that my hand was faster than my foot and I just had to relearn how to drive my car. Well, that issue got so bad a few weeks ago that the car no longer will release the clutch...period.

A little history...the car USED to have a dual-diaphragm pressure plate in it that was so hard to press that a longer clutch arm was needed to make it even remotely drivable. That pressure plate crapped out and was replaced by a TIII PP until around March when I swapped the entire clutch and flywheel assembly for a TU competition lightened flywheel, and 6-puck/purple plate combo all bolted down with ARP stuff. The trans is a rebuilt unit from Cliff Ramsdell with a chromoly endplate and OBX diff with a 555/520 hybrid gearset in it.

OK...on the the meat of the issue. So, I proceeded to try and diagnose this issue. I found that if I jack up the arm on the tranny the clutch does fully disengage and the arm does not touch the boss the cable runs through.

I thought that maybe my home made cable retainer might have been the issue, so I replaced it with a very good stock rubber piece. That had no effect.

For a while every now and then the adjuster would catch a different tooth and the clutch would be better, until it slipped to the previous adjustment it was at. After messing with it I found that if I pulled it down manually I could make the adjuster get to a point that would allow the clutch to disengage with normal pedal travel, so I figured the adjuster was bad. I attempted a temporary fix by jacking the arm up to the point where the clutch was dinegaged, pushing the pedal to the floor and putting the adjuster at that point and forcing it to stay at that adjustment by jamming it. This seemed to work with the exception that it kept constant tension on the clutch arm and I coul have sworn I felt the clutch slip once while driving it like this, telling me that it's holding the pressure plate slightly off of fully engaged.

Well, I replaced the whole shebang today and it made NO difference! The adjuster is almost all the way up in the pedal and has PLENTY of travel to come down some, however without a really strong spring on the adjuster, or preloading the arm the way I did before, it won't move down at all.

I'm thinking that the cable is stretching while under tension therefor not transmitting the full displacement of the pedal to the arm to disengage the clutch. I want to know how likely I am to being right on that?

I'm going to replace the cable this weekend hopefully, just to see it that's the issue.

I'd like feedback from other people on things I can try or have worked WITHOUT pulling the tranny or putting too much preload on the arm so as to make the clutch slip because the PP isn't pressing against the disk as hard as it's supposed to.

Thanks for the help!

[turbovanman²]

Honestly sounds like a stretched clutch cable.

Can you shim the cable up off the trans to tighten it up?

[puppet]

Just curious ... how many miles on the PP ?

[Reaper1]

Honestly sounds like a stretched clutch cable.

Can you shim the cable up off the trans to tighten it up?

I've kinda been thinking the same thing. I don't know about the shimming, but I can try. The only question I have is that isn't the adjuster supposed to take care of the eventual stretch of the cable? The only scenario I could come up with where it wouldn't is if the cable was stretching while pedal was being pressed, and this is where the adjuster can't do anything about it.

Just curious ... how many miles on the PP ?

I don't have a working odometer(typical) but I'd guess around maybe 10-12k miles...

[RoadWarrior222]

Haven't had this issue myself, but some thoughts about the type of cable involved from my experience with them in other applications...

They usually stretch with initial use over a few weeks, guess it depends how much you use it, but then they usually settle down to a fairly constant length after that with a lot less "spring"... So if you mean you put a fresh cable in, then you've got that period to go through again...

These cables also will tend to have a lot of slop in the more unsupported they are. It allows force to be dissipated by the cable flopping the outer around. You get a more positive action if you can support the cable at more points. See if you can ziptie it to a couple of extra supports while keeping it flexible enough to support some movement between transmission and firewall.

[Pat]

I've kinda been thinking the same thing. I don't know about the shimming, but I can try. The only question I have is that isn't the adjuster supposed to take care of the eventual stretch of the cable? The only scenario I could come up with where it wouldn't is if the cable was stretching while pedal was being pressed, and this is where the adjuster can't do anything about it.



I don't have a working odometer(typical) but I'd guess around maybe 10-12k miles...

Unless the cable is elastic, I don't see how the adjuster would not take up the slack in the cable provided it's working correctly. Shimming the cable at the clutch arm wouldn't fix the issue...you stick a few washers up there and the cable just moves up a few teeth on the self adjuster. One cancels out the other.

Honestly, I'd check to see if you are having some crank walk/worn thrust bearing issues. Dual diaphram plates, which you mentioned you had, are rough on thrust bearings. I"ve taken apart two motors that ran with dual diaphram plates and both had trashed thrust bearings. One of them sounded fine when it ran, but when you stepped on the clutch, you could watch the crank pulley move.

If the crank is moving a bit, theoretically, that could cause the clutch not to completely disengage.

[135sohc]

The self adjuster can only take but so much slack out before its at the end of its range of movement/adjustment. Been there, done that, replaced that cable. clutch worked great again afterwards.

Old cable was about 5/8" longer than the new one.

[Pat]

The self adjuster can only take but so much slack out before its at the end of its range of movement/adjustment. Been there, done that, replaced that cable. clutch worked great again afterwards.

Old cable was about 5/8" longer than the new one.

He mentioned that there is plenty of adjustment left in the self adjuster...it's not bottomed out.

[Captain Chaos]

Unless the cable is elastic, I don't see how the adjuster would not take up the slack in the cable provided it's working correctly. Shimming the cable at the clutch arm wouldn't fix the issue...you stick a few washers up there and the cable just moves up a few teeth on the self adjuster. One cancels out the other.

Honestly, I'd check to see if you are having some crank walk/worn thrust bearing issues. Dual diaphram plates, which you mentioned you had, are rough on thrust bearings. I"ve taken apart two motors that ran with dual diaphram plates and both had trashed thrust bearings. One of them sounded fine when it ran, but when you stepped on the clutch, you could watch the crank pulley move.

If the crank is moving a bit, theoretically, that could cause the clutch not to completely disengage.

Wow thats interesting. Who'd a thunk.

[Reaper1]

Well...hopefully at some point tomorrow I'll work on this issue. I'll definitely look for the crank pulley moving!

I *might* try shimming, but as I suspected, and has been pointed out, this probably won't solve much.

Given I don't see the crank pulley moving, I'll replace the cable.

It's nice to know about how to get more positive feel on the clutch. That is always a plus, so I'll give that a go as well.

Hopefully I can report back with some good news! I suppose we'll see!

[Reaper1]

OK...I replaced the cable with a known good unit. Before I installed it I checked the length against the one I pulled out of the car. If there was a difference, it was VERY small.

As suspected, replacing the cable did NOTHING for my issue.

I tried to start the car with it in reverse and the clutch pedal depressed and the started tried to roll the car backwards. This indicates that the clutch arm isn't moving far enough to disengage the clutch.

I also looked to see if the crank pulley was moving while the pedal was being pressed. I saw no movement there.

I DID see movement of the sheath of the cable at the transmission. One of my IC pipes kind of blocks the original path of the cable, so it comes in at a slight angle. This has never presented an issue before, but I did notice the sheath moving around as the pedal was being pressed. So, I'm going to remove the offending IC pipe and see what that nets me. The only thing is that the particular pipe I need to get to is NOT a lot of fun to remove...requiring most of the driver's side of the engine bay to come out. Oh fun Plus, I want to try shimming it with washers, which I don't have right now.

So, for now this is on hold. I'm still open for suggestions for things to look for and try before I go yanking the tranny out!

[shelbymonster]

you can move the arm on the trans where the cable end is 1-3 teeth and after adjust the pedal

[Reaper1]

Correct me if I'm wrong, but that would require unkeying the arm, right?

[shelbymonster]

there is spline all around the shaft

[Mario]

The shaft is keyed. It only goes on one way.

[Reaper1]

Yeah, but the shaft and the arm are keyed, so I'd have to grind the key on the arm.

I was thinking about this today, and I don't know that it would work this way either. The arm will still only travel a certain amount of rotation, which doesn't seem to be far enough right now. The cable is not stretched, and the adjuster is almost at the top of the pedal meaning that moving the arm down may not be possible as it might max out the adjuster. And even so, like I said, the travel will still be the same.

I'm going to try shimming the cable as has been suggested by a few people. I'm not 100% that this is going to work either, but I figure I'll give it a go...

[bakes]

pm Bent he had some problems with the wrong arms or some thing on his beast at one time.

[Pat]

Yeah, but the shaft and the arm are keyed, so I'd have to grind the key on the arm.

I was thinking about this today, and I don't know that it would work this way either. The arm will still only travel a certain amount of rotation, which doesn't seem to be far enough right now. The cable is not stretched, and the adjuster is almost at the top of the pedal meaning that moving the arm down may not be possible as it might max out the adjuster. And even so, like I said, the travel will still be the same.

I'm going to try shimming the cable as has been suggested by a few people. I'm not 100% that this is going to work either, but I figure I'll give it a go...

Shimming it accomplishes the same thing as re keying the arm. It's still the same travel at the arm.

Have you verified that everything guiding the cable is still in place and not worn out/moving around? Look at the guide at the top of the clutch pedal, check the bracket on the strut tower to make sure that's not moving around, double check to make sure the cable sheath is intact, etc.

[Reaper1]

Shimming it accomplishes the same thing as re keying the arm. It's still the same travel at the arm.

Have you verified that everything guiding the cable is still in place and not worn out/moving around? Look at the guide at the top of the clutch pedal, check the bracket on the strut tower to make sure that's not moving around, double check to make sure the cable sheath is intact, etc.

I'm going to try the shimming after talking with Brent. I think I might understand how and why it works with this set-up...finally!

I've replaced the entire clutch pedal, quadrant, adjuster, cable and retainer on the tranny with absolutely NO change in the issue.

Everything is in place, and everything is in good order(including the little clip on top of the quadrant to keep the cable from coming out of the groove if there is slack) that is directly visible without pulling the tranny.

I also verified that the engine pulley is not moving when the clutch is being depressed...a crude way of checking for crank walk. Also, the bellhousing is not moving away from the block, eliminating the possibility of that issue.

I'm also going to call my clutch supplier tomorrow to see if he has any suggestions, just to be sure. I'm not giving up hope that I can solve this without pulling the stupid transmission!

Oh, I forgot to mention, the tranny is an A555. While it "could" be a case of the wrong arm, it was working before, and IIRC I got this arm off of another A555 I have. I modified the original arm when I had that DDPP. I'm considering trying that arm again, but it is not easily accessible to me right now.

[Vigo]

Ive had my aries trans out 4 times or so in the last 2 months for clutch things. My problem is fixed. I think in the long run you will be fixed faster by just pulling it out and laying eyes on it..

Did you try what i suggested?