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Discussion Starter #1
OK, got my car all back together, runs great! Took it out to go cruising nad when I hammer on it, the clutch is hard to push, doesn't release all the way and the pedal hangs up down low for a second. I know my Z28 would do this and it was a common issue on them, but my GTO has been fun until I took it out today. Is it usually just a bum clutch, or is there something else I should look for? It is odd that the clutch is physically harder to push in when it does this.
Joe
 

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mine seems to do that to when i run it at the track. probably clutch wearing. that is the only time it happens
 

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Do the clutch hydraulic lines have restrictors in them like the F-bodies do? If so, it sounds like you need to pop the line out of your car and drill out the restrictor (the so-called "drill mod").
 

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from my understanding the drill mod won't work on ours (like it won't work on the late, late f-body's). I know some have been able to fix it changing fluid, changing slaves, and/or changing clutchs.
 

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Discussion Starter #5
Just sucks that it was ok three weeks ago when I parked it and now it is doing this. This car keeps pissing me off lately. If I wasn't so buried in it, I'd part out the mods and trade it in towards a C6!!!
Joe
 

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My clutch did the same exact thing after I got a cam package put on (415 rwhp).

I could not run wide open (drag race) though 2 gears without the clutch sticking to the floor. I just happened to be selling my GTO so I removed some of the mods (significant power loss) and the clutch worked perfectly again.

So it seems to me it has to do with the clutch being over powered in the high rpm range under full accelleration. You most likely need a stronger clutch to completely solve the problem.
 

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HPT Street Tuner
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my clutch was doing the same until i replaced the fluid. i have 415hp to the wheels, and my clutch is holding up fine, is stronger of what i thought is going to be.. my clutch used to get spongy even when i was bone stock and was making 1/4 mile passes. i didn't notice any difference in the way it was working with either 350rwhp (stock) or 415rwhp (modded).

bleed the old fluid out, or replace it little by little like i did, unless your clutch is really messed up, you don't need anything else
http://www.ls1gto.com/forums/showthread.php?t=106974
 

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1965 and 2005 GTO Owner
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It's called overcentering and is a common problem in all diaphram style clutches. What happenes is under high rpms the diaphram fingers get pushed beyond the center line and the clutch pedal sticks to the floor until the rpms drop. Two cures one high buck one real cheap.
High buck get a new clutch that cures the over center problem. You can either get a high performance diaphram model or go to a Borg & Beck style
Real cheap. Tape or wire tie a piece of wood to the clutch pedal. What you are trying to do find the point where the clutch is fully released but further pushing on the pedal only pushes the clutch over center. This is usally 1-2" off the floor but you need to experiment.
 

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What's in your wallet?
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If you're using a Diaphragm clutch that may be an issue too. Had that problem with the Stang when it hit the 11's. Went to a Long Style clutch and problem was solved.
 

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Discussion Starter #10
theamcguy said:
It's called overcentering and is a common problem in all diaphram style clutches. What happenes is under high rpms the diaphram fingers get pushed beyond the center line and the clutch pedal sticks to the floor until the rpms drop. Two cures one high buck one real cheap.
High buck get a new clutch that cures the over center problem. You can either get a high performance diaphram model or go to a Borg & Beck style
Real cheap. Tape or wire tie a piece of wood to the clutch pedal. What you are trying to do find the point where the clutch is fully released but further pushing on the pedal only pushes the clutch over center. This is usally 1-2" off the floor but you need to experiment.
That's what it seems like, however the odd thing is when it does it, the clutch does not release all the way either and I have to push it out of gear and wait for the RPM's to come back down. The pedal is also harder to push down when this happens, which I find odd.. Thank you for the reply, I may have to experiment tomorrow!!!


Also- are the Spec clutches diaphragm style or not? I have yet to see one in person. Thanks.
Joe
 

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Who me, no not me...
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OK, I've had this same problem now a few times over the last few weeks but usually only in very high speed runs (over 120 mph). I can shift at redline in other gears and be just fine, but 4th to 5th, and 5th to 6th is where I have had the problem.

I have the LS7 clutch sitting in my garage and I'm hoping that since it's rumored to have a lower release point, that pushing it past it's center point is virtually impossible.

Does anyone else have stories of this problem and what they did to fix it?
 

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It was a...
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I'm having the problem right now (see related threads). It does seems to happen at high load, high RPM conditions, so maybe the clutch isn't totally toasted yet? Once the speed slows down for a few seconds I can get back to going normally again.

Truckracer, did you wind up using regular old DOT4 or no? Might be a cheap attempt at a fix for now?
 

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i flushed mine out with some fresh dot 4 and clutch feels like it did when new, or close to that anyway.
 

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Discussion Starter #14
I swapped the clutch out anyway, so problem solved for me :). If anyone wants an 8k mile stock LS2 clutch- plenty of meat on the disk, just don't know if there is a PP problem or not, let me know lol. Probably a good replacement for someone stock.
Joe
 

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kwiktsi said:
I swapped the clutch out anyway, so problem solved for me :). If anyone wants an 8k mile stock LS2 clutch- plenty of meat on the disk, just don't know if there is a PP problem or not, let me know lol. Probably a good replacement for someone stock.
Joe
which clutch did you go with, and did you think the stock slave cylinder was in no way to blame?
 

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Discussion Starter #16
I went Spec-(yes, I can read- but I have had good luck with them in the past :)). With My Z, it was slave related because when you would jump on it, the pedal would get soft like the slave was "collapsing"- so I changed the slave and it got better. On the GTO, my clutch got physically hard to push in when it did this, which pointed to something mechanical binding. New clutch shifts fine at any RPM. However, I did go with Dot 5 while it was apart, so it could have been either- but the fact that it got harder makes me lean more towards the pressure plate acting up at high RPM's- it was fine with normal driving and even hard driving with lower rpm shifts.

Either way- there is no way the stock clutch was going to hold much longer at this level.
Joe
 

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kwiktsi said:
it was fine with normal driving and even hard driving with lower rpm shifts.
Joe
See, mine does it when I am through with a high speed run, I take it up to say 140, and then as I am slowing down I either want to throw it in 6th to get my RPMs down or 4th to help me slow down and when I clutch, and try to shift it grinds like the clutch is not depressed.

When I let off of the clutch it is forcing my foot up for about the first inch and then the pedal is just loose the rest of the way up to resting position. I stomp back down on it and then I can put it into gear. It's like it is sticking to the floor but not sticking "open" where I can change gears.
 

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Discussion Starter #18
That is what my camaro would do- it felt almost like the centrifigul (sp?) force would cause the pressure plate fingers to expand and push the throw out bearing/slave cylinder back a bit, so when you push the pedal, most of the travel went to just pushing it back and it would not release the disk all the way. My GTO was doing the same thing, but it was hard to push, where the camaro would be excessively soft when I'd go to push the pedal in.. I think the reason the pedal sticks down is because the pressure plate isn't pushing back on the slave since it was never really compressed to begin with. Kind of like if you bleed a clutch- the pedal will sitck down since the pressure plate it not being pushed against to spring the clutch back up.

I hope this kind of makes sense, I am doing 100 things at once here lol.
Joe
 

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It does make since. Looks like I need to proceed with my clutch install sooner rather than later.
 
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