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Clutch won't disengage after rebuild

 
Old 07-12-2019, 10:34 AM
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Shift Point
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Default Clutch won't disengage after rebuild

I spent the better part of the last six months rebuilding my 05 Z51 after the timing chain broke and made a mess of my valves. I have everything buttoned up, the engine runs fine, but I can't put the car in gear even with the wheels off the ground. The clutch is not disengaging at all.I'm using the stock clutch, it was still pretty new and in good shape. Things I've already done:
  • Friction plate orientation is correct
  • New pilot bearing
  • New slave
  • Input shaft clean & lightly greased
  • System properly bled with remote bleeder
The only thing I can possibly think to replace is the master cylinder, which I plan to do tonight. The clutch pedal feels pretty good and makes a full return, but maybe it has a small internal leak?
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Old 07-12-2019, 12:19 PM
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No real help here, but to me it can only be:

Pressure plate
Slave/TO bearing
Master

I've read that it is possible that if you use the bellhousing bolts to bring the torque in that you can cause the input shaft to miss align with the pilot bearing . I don't know if that's true however.
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Old 07-13-2019, 06:10 PM
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Originally Posted by Dutch08 View Post
No real help here, but to me it can only be:

Pressure plate
Slave/TO bearing
Master

I've read that it is possible that if you use the bellhousing bolts to bring the torque in that you can cause the input shaft to miss align with the pilot bearing . I don't know if that's true however.
I installed a new master last night, still a no go. I also didnít use the bell housing bolts to draw it in, I was able to push the input shaft in the whole way by hand. Iím at a loss here
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Old 07-14-2019, 11:55 AM
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Originally Posted by Shift Point View Post
I installed a new master last night, still a no go. I also didnít use the bell housing bolts to draw it in, I was able to push the input shaft in the whole way by hand. Iím at a loss here
Looks like you need to pull the torque tube again to have a look at the problem. :-(

(Again guessing and thinking out loud) I just DIY a clutch about 3 months ago. The only problem I can remember was getting the master to bleed and fill with fluid. I'm going to assume you installed a remote bleeder you might try putting a pressure gage on the end to make sure you are pressurizing the system adequately.

Does it grind when the engine is running and try you to put it in gear? Maybe you forgot to hook up the reverse lock out (05 has two!) or the skip shift (?).

If you figure out the problem be sure to post the answer! I'm very interested in this one.

Mine is an 05 with a LS7 clutch, new flywheel, new slave, and remote bleeder, if it helps.
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Old 07-15-2019, 09:35 AM
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Originally Posted by Dutch08 View Post
Looks like you need to pull the torque tube again to have a look at the problem. :-(

(Again guessing and thinking out loud) I just DIY a clutch about 3 months ago. The only problem I can remember was getting the master to bleed and fill with fluid. I'm going to assume you installed a remote bleeder you might try putting a pressure gage on the end to make sure you are pressurizing the system adequately.

Does it grind when the engine is running and try you to put it in gear? Maybe you forgot to hook up the reverse lock out (05 has two!) or the skip shift (?).

If you figure out the problem be sure to post the answer! I'm very interested in this one.

Mine is an 05 with a LS7 clutch, new flywheel, new slave, and remote bleeder, if it helps.
The master was bench bled and I wasnít getting any bubbles at all through the bleeder after 5 mins or so of bleeding. Iíd be open to trying a pressure gage, Iím not sure what this system should be pressurized to.

When the engine is off, I can go through all the gears. When I start the engine in neutral, Iím unable to shift into any of the gears. I donít really hear any grinding but it just wonít go. I also canít turn the wheels at all by hand while itís on a lift and the clutch is depressed. I am able to start the car in gear while itís on a lift and the wheels will turn and I can shift through the gears.
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Old 07-15-2019, 09:41 AM
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Pic of the pressure plate. Is it possible the forks got bent inwards during install?

[img]blob:https://www.corvetteforum.com/21533153-2caa-49a9-b648-d4ba2abd374b

Last edited by Shift Point; 07-15-2019 at 09:43 AM.
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Old 07-15-2019, 03:06 PM
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This one is a head scratcher!!!!

Originally Posted by Shift Point View Post
The master was bench bled and I wasn’t getting any bubbles at all through the bleeder after 5 mins or so of bleeding. I’d be open to trying a pressure gage, I’m not sure what this system should be pressurized to.
Did you bleed the ENTIRE system, that is the master and slave connected together through the bleeder on the slave ? If not that's probably the problem.

Originally Posted by Shift Point View Post
Pic of the pressure plate. Is it possible the forks got bent inwards during install?
Hard to tell from the pic, but isn't "inwards" a clutch release ?

Other guesses on my part.
  • Pressure plate is bad
  • Did you measure for a slave/TO bearing shim?( How to measure here ==> https://www.tickperformance.com/tick...im-kit-3-pack/)
  • Pilot bearing frozen (You said you bought a new one, but just thinking of what it could be.)
  • You did reconnect the quick disconnects all the way in and put the retainers back in. (Or connected with the retainers in until the "click")

Last edited by Dutch08; 07-15-2019 at 03:24 PM.
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Old 07-15-2019, 03:48 PM
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Originally Posted by Dutch08 View Post
This one is a head scratcher!!!!



Did you bleed the ENTIRE system, that is the master and slave connected together through the bleeder on the slave ? If not that's probably the problem.

Yes - I bled the entire system with a remote bleeder until I saw zero bubbles and the clutch made a full return on its own.

Hard to tell from the pic, but isn't "inwards" a clutch release ?

Yes - not sure if that could be the problem or not. Perhaps it lost its spring constant?

Other guesses on my part.
  • Pressure plate is bad Seems unlikely since it worked fine when I disassembled it. I just ordered a new LS7 clutch kit & aluminum flywheel to be safe
  • Did you measure for a slave/TO bearing shim?( How to measure here ==> https://www.tickperformance.com/tick...im-kit-3-pack/) Yes -- The gap was about .050" iirc, which is actually a little on the lower side and should promote disengagement
  • Pilot bearing frozen (You said you bought a new one, but just thinking of what it could be.) I pulled the input shaft and clutch again yesterday (after 3 attempts I'm able to pull a clutch in about 2 hours now with a helper) -- new pilot still spins freely and is uniformly seated
  • You did reconnect the quick disconnects all the way in and put the retainers back in. (Or connected with the retainers in until the "click") Yes, inserted the metal clip and then connected until the click. Cannot pull apart
see above
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Old 07-16-2019, 03:11 PM
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bump. I have limited time on a lift here.. someone help please and thank you
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Old 07-16-2019, 04:12 PM
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Originally Posted by Shift Point View Post
bump. I have limited time on a lift here.. someone help please and thank you
You have a real brain buster here. Final guess and then I give up.

Pressure Plate jammed up - (You ordered a new one )
Shifter Assembly - did you center the shift rod before tightening with the GM pin or the center guide from the manufacturer ?

Please update when you figure it out, I'd really like to know the answer.
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Old 07-17-2019, 12:50 PM
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Originally Posted by Dutch08 View Post
You have a real brain buster here. Final guess and then I give up.

Pressure Plate jammed up - (You ordered a new one )
Shifter Assembly - did you center the shift rod before tightening with the GM pin or the center guide from the manufacturer ?

Please update when you figure it out, I'd really like to know the answer.
I never removed the shifter assembly, just took the **** off and dropped it down through the floor. Even with the car already in gear and the clutch depressed, i can't start the car without it trying to lurch forward. Suggests a clutch issue instead of a shifting issue to me. I'm going to try to install the new clutch kit tomorrow, I'll let you know how it goes
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Old Yesterday, 12:55 PM
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Hey any news (not to rush you) ? You can PM me if you would rather.
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Old Yesterday, 01:27 PM
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Originally Posted by Dutch08 View Post
Hey any news (not to rush you) ? You can PM me if you would rather.
Yes -- Good news! About 3am friday night we got everything buttoned up with the new clutch kit and it worked perfectly. I still have no idea what could have gone wrong, everything looks ok visually. I'm going to dissect the pressure plate and see if I can find anything. Thanks for all the suggestions
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