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stuck clutch - ideas?
I'm trying to resurrect a '75 911T with the 915 transmission and have a stuck clutch.
I initially thought that perhaps the clutch cable was badly stretched and replaced that, being careful to adjust correctly. Full clutch pedal travel yields only ~0.2" of clutch lever travel at the trans (enough to take up throw-out bearing slack, it seems). I have tried "bumping" the car with the starter while in gear with the clutch pedal depressed, and have tried "dragging" the car while doing the same in an effort to get the clutch plate to free up from the flywheel. Neither were successful. Couple of questions: - How much travel should I see at the end of the clutch lever at the trans when the clutch disengages? - Any other ideas on how to unstick this thing (short of dropping the motor/trans)? Thanks for the help. |
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08-31-2010, 06:27 PM
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Your doing the right thing, just be more aggressive with them, keep the clutch pedal in and have assistants rock the car in 4th gear. it should POP!
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08 Cayenne Turbo |
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08-31-2010, 07:35 PM
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Something is wrong if the arm is only moving .2 inches. Look at how far the cable moves in the foot well. That's how far it should move the arm. Does the pedal feel right? Does it come back up? You need to get the arm to move before you try to unstick the clutch (which it's probably not).
-Andy
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72 Carrera RS replica, Spec 911 racer |
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08-31-2010, 09:00 PM
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Yeah something wrong if after a clutch cable change and a adjustment he is only getting .2" movement at the clutch. I would check the pedal cluster for damage or broken parts.
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08 Cayenne Turbo |
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09-01-2010, 10:31 AM
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Hmmm - Good point on cable travel.
Pedal gets very "tight" within the first inch of pedal travel and then it requires lots of force to move further. During this time, the clutch arm is not moving. My assumption was that the clutch arm was stuck and that I was stretching/deflecting the pedal assembly, cable, and cable anchors. I'll disconnect cable, measure travel, and then further investigate for "loose stuff". Thanks for the help. |
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09-01-2010, 11:47 AM
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Check for a sheared roll pin on the pedal assembly.
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Pete 79 911SC RoW "Tornadoes come out of frikkin nowhere. One minute everything is all sunshine and puppies the next thing you know you've got flying cows".- Stomachmonkey |
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09-01-2010, 12:27 PM
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Clutch arm might indeed be stuck. This would imply a broken piece inside or the throw out bearing is stuck on it's guide tube. Also the clutch fork might be jammed on the wrong area of the throw-out bearing. In any case you'll probably have to pull the engine at least part way back to see what's going on. You can do a partial drop and pull the engine back about 2 inches from the tranny (leaving the long studs engaged in the bell housing). Then with flashlight and mirror you might be able to see the problem. Other option is to just drop the engine. This is how I always remove the engine and I think it's easier than undoing all the stuff on the tranny (cv bolts especially). Just make sure you undo the shift linkage in the tunnel. I also back off the front tranny mount bolts to give more clearance of the shift rod in the tunnel hole. Obviously you must support the tranny as you remove the engine.
-Andy
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72 Carrera RS replica, Spec 911 racer |
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09-01-2010, 12:37 PM
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Excellent ideas - thanks!
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09-01-2010, 06:07 PM
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After investigating further and reading up on the "clutch won't disengage" thread, I have ruled out pedal cluster faults. Back at the tranny, I did find that the vertical clutch input shaft has about 1/8" of vertical free play. Is that normal?
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09-04-2010, 06:36 AM
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Somewhere in the Midwest
Join Date: Oct 2001
Location: In the barn!
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MikeZ had a problem a while back with a clutch stuck problem. It was a workig clutch when they pulled the engine and tranny. They power washed the assembly and some water must have gotten on the clutch face. No matter what they did it would not disengage.
Turns out the moisture on the clutch face was enough to oxidize the clutch to the flywheel. They had to pull the drivetrain. I suspect you will have to pull the drivetrain and to over the things that can seize. Best to check everything out while is out of the vehicle anyhow. Good luck. |
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09-04-2010, 08:36 AM
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My clutch fork has about the same amount of play. I added a washer under the circlip to reduce the play by about 50 percent.
-Andy
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72 Carrera RS replica, Spec 911 racer |
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09-04-2010, 08:05 PM
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After validating pedal/cable travel, it looks like I am going to have to pull the engine/tranny to investigate. Not altogether a bad thing - there are several oil leaks, low compression on a couple cylinders, lots of cleanup to do, and I'm sure a host of other problems.
Now to find an engine stand... |
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09-06-2010, 05:39 PM
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1979 Porsche 911SC
