T56 Clutch won't Diesengage..
 

Just finished t56 swap can't figure out clutch won't disengage..

Parts used in the swap included:

New GM LT1 master / slavecylinder assembly
Resurfaced Stock LT1 Flywheel
New LT4 pressure plate
New Mcleod Clutch NOT street twin
New pilot bearing.
Used t56 4th gen trans

Clutch seems harder to push down than I think it should, but pedal has full range of motion, Clutch not disengaging- if started in gear wheels turn, If started in neutral, unable ro shift into any gear..

I'm at a loss on where to go... it seems like from searching it could be either either-

1) clutch fork, but mine seems like its in the correct position (slave cylinder rod is centered in dimple and I pushed it in and I think it snapped around the T-stud and throwout bearing allthough it does still have some play in it ?

2) Hydraulic problem maybe the firewall hole is off a little causing it to bind into master cylinder?

3) Clutch problem..

4) Somehing else

Any help from someone who has new outlook on this as I've been looking at the car doing the swap the last couple of days would be appreciated

Thanks

Tony

I'am sure you had this right but when you were putting the disk in did you have it facing the right way?

One way to check the hydrolics and the motion of the fork is to take out the spacer for the slave and use bolts on both sides of the slave to keep it in the same spot and have someone push your clutch peddle in while your looking whats going on.

On the slave cylinder, I removed the aluminum spacer, measuring the distance ( to keep it the same distance from the bellhousing, reinstalled the nuts and checked the movement and got between 3/8 and 1/2".. I think the shop manual says .40" or .41" so I think thats ok... I only hope I didn't install the disk backwards as it was marked "engine" on one side although as a last resort I'll take it apart and double check but trying to avoid that arrgghh...

Thanks for the suggestions

Hmmm I'am thinking you should be able to get close to 1" of movement, 3/8 to 1/2" seems kind of short. You might have some air in the system, take that slave off and point the rod end to the ground in a 45* angle, then I want you to pump that rod back and forth in its full range of motion tell its start to get hard and you feel no sponginess in it. This will get any air out of the system, also what generation of peddles did you use and where is the clutch peddle sitting compared to your brake peddle?

I checked and rechecked today.. finally took everything back out and and it looks fine but still won't disengage clutch

-1st I removed slave cylinder, depressed fork approximately 5/8 to 3/4" and still no disengagement. Figuring I ruled out the hydraulics I went ahead and took trans / clutch / pressure plate back out to have a look.

What I discovered was that everything looks correct??

-Clutch disk faced the correct way

-Pressure plate was the same as the old one that came out of the old car (LT4 pp)

-no apparent damage to throwout bearing or pilot bearing or input shaft..

- checked t-stud it was tight

-evidence of fork being seated corectly on throwout bearing as there were two slightly dirty marks in the light grease coating on it where it sits.

This leaves me puzzled :confused:

i had bought a hays clutch disc before... they put the "engine" sticker on teh wrong side. and i didn't know any better since it was the first time installing a cluth on a t56... may wanna triple check that... the "flat" side of the disc should go towards teh tranny.

Thanks, flat side is toward trans / pressure plate, I was hoping to find when I took the trans back out I did have it backwards so I could flip it around and be driving, but no such luck ..

Wow that kind of sucks, sound like everything is put together properly, only thing that sounds logical at this point is the pressure plate is no good :(

When you say you have a new Mcleod Clutch are you just talking about the disk or the whole clutch? Also can you do me a favor since you have the clutch out could you measure the thickness of that disk I would like to compare it to the ones I have at home.

Pressure plate is a new lt4 pp , clutch disk is .36 from the front friction surfaces to each other..

I know this may seem stupid but, is the throw-out bearing attached to the pressure plate? (I am sure the problem is just something simple and overlooked)

if it is attached, when everything is togeather (and you have the spacer/ cover off where the slave cyl goes) can you take a small pry bar or what ever will fit and pry forward on the clutch fork? you should beable to feel if it is working at the trans

Throwout bearing came with the lt4 pp, and assembled so I'm fairly sure its in right, I double checked everything again today reinstalled it, and still no disengagement of the clutch..

I bled the hydraulics, no air at all. Then when the clutch would not diesengage using the pedal I used the tool I made.. looks kind of like a steering weel puller on the two slave cylinder bolts to depress the clutch fork approximately 5/8" then it seems to come to a stop (possibly the other end on the front of the trans?) and at this point the clutch still is not disengaged. So I don't think the fork can bend since it's cast, its on the t-stud properly and its tight, so,,, possibly did I get a wrong / bad new pp GM 10222083 or clutch disk mcleod 261871 or are they not compatible or am I just missing somethig here..

Help...... I give up... It's now day 5 of what should have been a 2-3 day job...

Thanks for all the suggestions so far but it still doesn't work

you should be getting a bit of travel at the fork. mine would almost touch the pressure plate when pressed all the way down


did you take any pictures of the clutch when you had it out? there was a guy awhile back that was having problems and turned out he was sent the wrong clutch disc

At this point I'm thinking I'm not getting enough movement in the clutch fork from the slave cylinder as it is only moving app .38 to .40" and the gm MINIMUM spec (according to the shop manual for a 96 T56 hydraulic system is .43" (hydraulics are new and I bled them to be sure ok) It doesn't seem like much under the minimum but I wonder what TYPICAL extension of the slave cylinder is? If I'm a little under the minimum + mcleod clutch which upon furthur research appears to have some disengagement issues + l4t PP = not disengaging completely?

My thoughts are possibly trying another GM master / slave, maybe I got one made on a monday, an adjustable one, or a different clutch / pp?

Any thoughts?

whats the status on this?

What part number did you get? 40-221? Are you happy with it?

Mines the same way, with my adjustable master I'am 1/2 turn away from grinding my pressure plate.

Black89TA, I am having the same issue on my swap. What did you have to do to get the clutch to engage?

Slave cylinder should pushoutward atleast 7/8 in T5 applications. I'm not sure what it's supposed to be for the funky LT1 style clutch.

Maybe your pivot ball is not adjusted properly?

It was asked earlier but the orginal poster never responded. What generation of pedals are you using?

I am using 3rd gen pedals. My car was originally a 5 speed.

Other parts include:
New GM LT1 master / slave cylinder assembly
Resurfaced Stock LT1 Flywheel
New pressure plate
Clutch Masters stage 3 clutch
New pilot bearing
Used t56 4th gen trans

I am having the same problem Black89TA described.
Any help would really be appreciated. Thanks

Rick

It might be pedal related but no one has actually confirmed this because very few people have swapped from a T-5 to a T-56. Have you tried compressing the master manually (without the pedal attached) to see if that would work? I think there might be a slight difference in pedal movement.

Then again, if I can’t drive my car tomorrow that means that it’s not the pedals as I already installed a set of 4th gen pedals (the trans will be going in tomorrow). I will be sure to post an update. I installed new everything minus the flywheel which was machined down.

Re: T56 Clutch won't Diesengage..
 

I realize this is a really old thread but I'm having exactly the same issue and I want to know what's up.

I'm using a resurfaced RAM aluminum flywheel, slightly used stock clutch and pressure plate, and new hydraulics. I think I ruled out the hydraulics being an issue because I used a harmonic balancer puller to fully extend the clutch fork as far as it was willing to go and it sill wouldn't disengage. The only other thing I can think of is that the pressure plate is somehow at fault. How tight is the pressure plate supposed to be on the flywheel anyways?

Re: T56 Clutch won't Diesengage..
 

Yeah if the pressure plate bolts were too tight wouldn't that create this problem? Doing a T56 swap too right now. Hope I don't have this issue!

Re: T56 Clutch won't Diesengage..
 

They should not be overtightened and yes it can cause problems.
I use a torque wrench on next to nothing but have heard 22 ft lbs of tq referenced repeatedly.

Re: T56 Clutch won't Diesengage..
 

I did use a torque wrench set to 22 ft. Lbs

Re: T56 Clutch won't Diesengage..
 

22lbs! woops I torqued mine too about 36 ft lbs. 22 seems pretty weak imo.

Re: T56 Clutch won't Diesengage..
 

I usually torque mine more, be worried about stripping threads then causing a problem with the clutch.

You sure you have the fork seated proper around the throw out bearing?

Re: T56 Clutch won't Diesengage..
 

I think I may have discovered the issue. Please guys let me know if I could be right. There's a retaining clip that holds the throwout bearing on the pressure plate, right? When I pulled my transmission, I noticed that the clip was only holding two of the three prongs on the throwout bearing. My theory is that this would cause the pressure plate to disengage crooked, with perhaps one side released and one side still touching the flywheel. Right now this is my only theory. I took my clutch in to an auto shop and they say that the clutch looks perfectly fine. And I'm sure it's not the hydraulics because before I pulled the transmission I used a puller to fully push the clutch fork in.

Can somebody please let me know if my logic makes sense before I reinstall the transmission?

Re: T56 Clutch won't Diesengage..
 

Oh and the clutch fork was definitely seated properly because when I pulled the transmission I forgot to disengage the clutch fork and ended up having to push the tranny forwards again to be able to disengage it. It wouldn't have gotten stuck if the fork wasn't on the throwout bearing.

Re: T56 Clutch won't Diesengage..
 

Ok so I just reinstalled the transmission and now the clutch seems to be disengaging properly. I am very relieved at this and hopefully someone else can learn from this! The lesson is to make sure that the retaining clip on the throwout bearing is engaged on all three prongs of the throwout bearing. That's the only thing I changed when I reinstalled the transmission so I'm pretty sure that's the solution.