Archie Posted April 6, 2008 Report Share Posted April 6, 2008 Well AJ's been trying to work the bugs out on my '96 Z28's clutch replacement, But we've run into a problem with the clutch not fully disengaging. I've researched this problem a little bit but no success. Typically this problem is due to faulty hydralics, ie. slave cylinder, but this doesn't seem likely after working it by hand. One odd thing is that the throwout bearing seems too tall as the clutch fork has about 5/16" of play when its on the TO bearing. Hopefully some of the LT1 gurus on here can shine some light on this situation... Quote Link to comment Share on other sites More sharing options...
Archie Posted April 7, 2008 Author Report Share Posted April 7, 2008 nobody? Quote Link to comment Share on other sites More sharing options...
Brandon Posted April 7, 2008 Report Share Posted April 7, 2008 Check your part numbers, I have had an issue with having the discs packaged wrong before, what brand is the clutch. Quote Link to comment Share on other sites More sharing options...
AJ Posted April 7, 2008 Report Share Posted April 7, 2008 Check your part numbers, I have had an issue with having the discs packaged wrong before, what brand is the clutch. 2 different brands, same issue. the fork is 5/16 too thin when inside the bearing. which makes roughly an inch of movement back and fourth at the fork end. Quote Link to comment Share on other sites More sharing options...
Archie Posted April 8, 2008 Author Report Share Posted April 8, 2008 http://img.photobucket.com/albums/v716/z28toaz34/modifiedslave.jpg Adjustable slave rod... Might be a last ditch effort to fix it. Two screws, two nuts, and a sleeve. I'm thinking I need to try replacing the hydralics. Quote Link to comment Share on other sites More sharing options...
nathan Posted April 8, 2008 Report Share Posted April 8, 2008 You're sure the fork is completely on? The fork has to be slid up over the TO after you have everything back together. Did you have someone machine the flywheel and is it now too shallow? Quote Link to comment Share on other sites More sharing options...
Archie Posted April 8, 2008 Author Report Share Posted April 8, 2008 You're sure the fork is completely on? The fork has to be slid up over the TO after you have everything back together. Did you have someone machine the flywheel and is it now too shallow? As far as I know, AJ installed the fork just fine. He did resurface the flywheel, but wouldn't making it too shallow cause it to not fully disengage??? Quote Link to comment Share on other sites More sharing options...
Nitrousbird Posted April 8, 2008 Report Share Posted April 8, 2008 - Fork engagement on the TO Bearing. VERY important, as it can be a PITA to get right. Luckily, you don't have to pull the tranny. Just pull the slave and take a look. - Make sure the master/slave are perfect. - An overly machined flywheel "could" cause this, though I never personally dealt with that. - Disc probably isn't the issue, but how about the pressure plate? Any cracks ANYWHERE on it. I had a cracked one once that would basically bend under pressure just enough to not disengage. - What kind of clutch is it? All LT1 pressure plates are either stock or modified versions of the LT1 and LT4 PP's (which ARE different). Pretty much all performance clutches are a modified LT4 PP, all made by Valeo. Otherwise, I've heard of this issue on Centerforce Dual Frictions when they get hot, due to the weights they put on the pressure plate. Quote Link to comment Share on other sites More sharing options...
AJ Posted April 9, 2008 Report Share Posted April 9, 2008 - Fork engagement on the TO Bearing. VERY important, as it can be a PITA to get right. Luckily, you don't have to pull the tranny. Just pull the slave and take a look. - Make sure the master/slave are perfect. - An overly machined flywheel "could" cause this, though I never personally dealt with that. - Disc probably isn't the issue, but how about the pressure plate? Any cracks ANYWHERE on it. I had a cracked one once that would basically bend under pressure just enough to not disengage. - What kind of clutch is it? All LT1 pressure plates are either stock or modified versions of the LT1 and LT4 PP's (which ARE different). Pretty much all performance clutches are a modified LT4 PP, all made by Valeo. Otherwise, I've heard of this issue on Centerforce Dual Frictions when they get hot, due to the weights they put on the pressure plate. i didn't need to take much off the flywheel. no cracks in the pressure plate. Art. post up the pictures of the fork on the throw out bearing so everyone can see what we are dealing with. Quote Link to comment Share on other sites More sharing options...
Archie Posted April 9, 2008 Author Report Share Posted April 9, 2008 http://i48.photobucket.com/albums/f214/apietra/0406081459.jpg http://i48.photobucket.com/albums/f214/apietra/0406081512.jpg Quote Link to comment Share on other sites More sharing options...
smokin5s Posted April 9, 2008 Report Share Posted April 9, 2008 Also make sure that the hydrolics are all bleed... I've seen that on more than one ocassion where they weren't bled right and the clutch would never fully disengage. Quote Link to comment Share on other sites More sharing options...
AJ Posted April 9, 2008 Report Share Posted April 9, 2008 Also make sure that the hydrolics are all bleed... I've seen that on more than one ocassion where they weren't bled right and the clutch would never fully disengage. did it 3 diffetent times just to be sure Quote Link to comment Share on other sites More sharing options...
nathan Posted April 10, 2008 Report Share Posted April 10, 2008 Well its odd seeing it with just the bell housing on there, The TO bearing looks a bit different than some that I have seen, but it could just be the angle. I guess I am trying to figure out how you know if it is working right on the engine stand. Not saying that you can't tell, just not sure how you're testing it. Also, it does appear you need to push the fork on more, but I'm not sure since any time I have put one back together I push the fork back into place with the tranny already on. There is an adjustment on the fork itself to change the pivot amount. Don't know if you guys moved that or not, but might be something else to look at. Quote Link to comment Share on other sites More sharing options...
nathan Posted April 10, 2008 Report Share Posted April 10, 2008 Wait, did you take the fork off? It almost looks like it might be on backwards. Quote Link to comment Share on other sites More sharing options...
Archie Posted April 10, 2008 Author Report Share Posted April 10, 2008 The fork WAS removed. I don't think the fork is on backwards because of the clip that holds the fork in place once you bolt the tranny up... The Pressure Plate/TO is just a LT4. After getting a stock TO from Autozone, there was no difference in height, which could cause it to not disengage. I didn't know the pivot on the fork could be adjusted... Maybe AJ can clarify a little more. Quote Link to comment Share on other sites More sharing options...
AJ Posted April 10, 2008 Report Share Posted April 10, 2008 there is no adjustment in the fork, it can only bolt in one place and will not go on if turned around. the extra 5/16" is causing all our problems. Quote Link to comment Share on other sites More sharing options...
nathan Posted April 11, 2008 Report Share Posted April 11, 2008 http://www.camaroz28.com/forums/search.php?searchid=2332710 I don't know if you guys can link to it, but if you're members over at this site search for clutch fork bolt or something similar. Quote Link to comment Share on other sites More sharing options...
Archie Posted April 11, 2008 Author Report Share Posted April 11, 2008 http://i48.photobucket.com/albums/f214/apietra/trannywforkinstalled.jpg I don't see anything different... Quote Link to comment Share on other sites More sharing options...
Guest 614Streets Posted April 11, 2008 Report Share Posted April 11, 2008 With the car on the lift and someone in the car how much travel are you guys getting at the slave? Quote Link to comment Share on other sites More sharing options...
AJ Posted April 11, 2008 Report Share Posted April 11, 2008 With the car on the lift and someone in the car how much travel are you guys getting at the slave? full travel, been there done that. the whole problem is the throw out bearing, we just can't find the right one as i can't order one with paying $160 for it just to see if its right from GM. Art, the LT4 and LT1 bearings are different part numbers from GM. i had them look it up hopeing it had some measurements listed. Quote Link to comment Share on other sites More sharing options...
Archie Posted April 12, 2008 Author Report Share Posted April 12, 2008 I called valeo yesterday and talked to a 'tech guy'... He pretty much told me that all the TO's that are used on Valeo's PPs are the same height. He reiterated what Joe said about all the aftermarket clutch kits being mostly LT4 pressure plates and they also typically use the LT4 TO. As we've seen the only difference is the shape of the TO (LT4 is square), and it is supposed to be a little more heavy duty. He also gave me all the bullshit about bad hydralics, overmachined flywheel, fucked up pressure plate, ect. One thing he did say that was interesting was that people had disengagement issues if they torqued the shit out of the bolts that held the pressure plate on... he said to follow the torque specs very carefully (44 ft/lbs?). AJ, if I cant figure anything out by the end of today just slap it back together and I'll sell this POS. Quote Link to comment Share on other sites More sharing options...
nathan Posted April 18, 2008 Report Share Posted April 18, 2008 did you guys see check the camaroz28.com site? Some people described what you are experiencing, but cliff notes was that you might have to grind a little bit off the fork and it will fit better. Must be a machining issue that some of the forks had as opposed to others. Quote Link to comment Share on other sites More sharing options...
AJ Posted April 18, 2008 Report Share Posted April 18, 2008 did you guys see check the camaroz28.com site? Some people described what you are experiencing, but cliff notes was that you might have to grind a little bit off the fork and it will fit better. Must be a machining issue that some of the forks had as opposed to others. fork fits the bearing it just has too much travel before it engauges the pressure plate. Quote Link to comment Share on other sites More sharing options...
hpfiend Posted April 18, 2008 Report Share Posted April 18, 2008 Maybe the fork is bent? Did you try a new fork? I am surprised no dealers in columbus have another throwout bearing- what about aftermarket??- I am sure if you didn't marr it you could return it... Quote Link to comment Share on other sites More sharing options...
Archie Posted April 18, 2008 Author Report Share Posted April 18, 2008 OK, I had the guy at Valeo pull a TO and measure it... Total height of the TO bearing - 43.5 MM Inside dimension of the area where the fork engages - 19.8 MM He also said you need that 5/16" play in there so the fork won't jam on the TO. AJ, if you want to hear it for yourself just call (888) 71-VALEO, they are very helpful. I think the hydralics are trashed... Quote Link to comment Share on other sites More sharing options...
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