lt1 clutch issues
Thread Starter
On The Tree
Joined: Dec 2008
Posts: 109
Likes: 0
From: Lino Lakes, MN
lt1 clutch issues I have a thirdgen with a lt1 style t56 and a spec 3 clutch. The pedal will not fully disengage even when pressed to the floor and it grinds when I try to shift. I have bled it several times and everything is working fine. My guess is I need to shim the slave? Where can you buy these because not a single parts store I have went to even knows what im talking about. Also, how do I know how much to shim? I have also heard you can shim the flywheel as well, is this possible?
.....and yes I have used the search button
.....and yes I have used the search button
TECH Regular
Joined: Oct 2008
Posts: 492
Likes: 0
From: Rochester, NY
You can't shim the flywheel and itd be totally pointless to shim the slave since its self adjusting. I think with the LS1s with their interal release bearing setups they can be shimmed but LT1s are a totally different story.
The amount of potential travel the slave cylinder has is enormous but it will only push as far as the master cylinder at the pedal will push it. Basically if you made up some sort of shim to move the position of the slave forwards or backwards, once you bolted it back on the car it would automatically adjust to the new location from the clutchfork and thatd be you new starting push point. Same thing with shimming the flywheel-- I've learned that the flywheel can be resurfaced a pretty much an unlimited amount of times without any failure. Since LT1s have a pull-type clutch, the thinner the flywheel is, the the closer the clutchfork is positioned to the slave cylinder making it even less likely that the slave wont have enough reach to disnegage (and also rendering shims useless). The slave has like 3-4" of potential travel but only it needs to push the fork roughly 1/2" to fully disengage the clutch disks, understand?
Logically bleeding the clutch would be the first guess but if youve bled the heck out of it and problems still exist then something else obviously must be causing this, most likely a hydraulic problem. You may have an interal fluid leak in the master or slave. Someone else may chime in with a better possible solution but... if I were you I'd try replacing the some components of the hydraulic system one at a time. Start off with replacing the slave since its relatively cheap and easy, bleed it and hopefully that may solve your problem.
You may wanna give SPEC a call too, their tech guys are usually pretty helpful.
The amount of potential travel the slave cylinder has is enormous but it will only push as far as the master cylinder at the pedal will push it. Basically if you made up some sort of shim to move the position of the slave forwards or backwards, once you bolted it back on the car it would automatically adjust to the new location from the clutchfork and thatd be you new starting push point. Same thing with shimming the flywheel-- I've learned that the flywheel can be resurfaced a pretty much an unlimited amount of times without any failure. Since LT1s have a pull-type clutch, the thinner the flywheel is, the the closer the clutchfork is positioned to the slave cylinder making it even less likely that the slave wont have enough reach to disnegage (and also rendering shims useless). The slave has like 3-4" of potential travel but only it needs to push the fork roughly 1/2" to fully disengage the clutch disks, understand?
Logically bleeding the clutch would be the first guess but if youve bled the heck out of it and problems still exist then something else obviously must be causing this, most likely a hydraulic problem. You may have an interal fluid leak in the master or slave. Someone else may chime in with a better possible solution but... if I were you I'd try replacing the some components of the hydraulic system one at a time. Start off with replacing the slave since its relatively cheap and easy, bleed it and hopefully that may solve your problem.
You may wanna give SPEC a call too, their tech guys are usually pretty helpful.
