LS7 clutch problem?
Thread Starter
Racer
Joined: Nov 2006
Posts: 380
Likes: 1
From: Janesville Wisconsin
LS7 clutch problem?
I have a 99 that I just put an LS7 clutch/LS2 flywheel in and new GM slave... and have bled it a million times. The shifter seems notchy now and the clutch engages almost immediatly upon releasing the pedal. Is there anything im overlooking or does it need to be bled a million more times? Bleeding it doesnt seem to make it any better.
Pro
Joined: Dec 2009
Posts: 606
Likes: 1
From: Waco Texas
Pro
Joined: Mar 2004
Posts: 653
Likes: 0
Pump the pedal a few times.
Release the pedal.
Crack open the bleeder.
Have a helper slowly depress the clutch pedal.
Close the bleeder when the pedal is near the floorboard.
Top off clutch reservoir.
Repeat four times, for a total of 5 iterations.
Test drive and observe transmission shifting behavior.
If still notchy, whip out your MityVac and apply vacuum to the reservoir feed line for ~15-20 minutes...check the MityVac clear line for bubbles.
The way you're doing it, you don't move much fluid and therefore don't displace the air bubble(s) effectively. You can bleed it that way for hours and still have air.
Pro
Joined: Apr 2007
Posts: 635
Likes: 0
From: Mc Farland Wisconsin
This is just a suggestion, I have no idea if it would be the case as I have never seen one in person. I put a clutch in my mom's toyota solara BACKWARDS. The disc had one part of the sleeve larger on one side than the other. It did this EXACT same thing that you are describing. I figured this out after I replaced her master as well......Anybody want to chime in on if they are symmetrical or not?
Pro
Joined: Mar 2004
Posts: 653
Likes: 0
This is just a suggestion, I have no idea if it would be the case as I have never seen one in person. I put a clutch in my mom's toyota solara BACKWARDS. The disc had one part of the sleeve larger on one side than the other. It did this EXACT same thing that you are describing. I figured this out after I replaced her master as well......Anybody want to chime in on if they are symmetrical or not?
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Melting Slicks
Joined: Feb 2007
Posts: 3,266
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From: Indian Rocks Beach FL
St. Jude Donor '08-'09-'10
Melting Slicks
Joined: Jun 2005
Posts: 2,396
Likes: 52
From: Sicamous BC
When my LS7 clutch & flywheel were installed I found the same situation. I was told that was normal & as the clutch broke in there would be improvement.
I think I probably went thru a 5 gal pail of hydraulic fluid trying to improve it. Bleeding did not do anything. After some break in & some aggressive moments with the clutch there was a marginal improvement.
I did purchase a Tick M/C that I was going to try & never did due to engine failure. I see now there is another choice with adjustable M/C that look's interesting.
When I was searching that close to floor engagement there appeared to be a hit or miss with the problem. I also remember something about a shim.
I think I probably went thru a 5 gal pail of hydraulic fluid trying to improve it. Bleeding did not do anything. After some break in & some aggressive moments with the clutch there was a marginal improvement.
I did purchase a Tick M/C that I was going to try & never did due to engine failure. I see now there is another choice with adjustable M/C that look's interesting.
When I was searching that close to floor engagement there appeared to be a hit or miss with the problem. I also remember something about a shim.
Last edited by CTD; Oct 5, 2010 at 08:30 PM.
Advanced
Joined: Jul 2010
Posts: 68
Likes: 0
From: Pittsburgh PA
I was under the same impression. The LS7 flywheel, pressure plate, disc, are usually sold as a package?
When I installed the LS7 clutch, I bled it repeatedly and it still engaged very close to the floor. Pump the **** out of the clutch pedal (100-150 times). The pedal should come up. Drive the car and you will probably notice the pedal progressively comes up over a period of 2 weeks or so.
When I installed the LS7 clutch, I bled it repeatedly and it still engaged very close to the floor. Pump the **** out of the clutch pedal (100-150 times). The pedal should come up. Drive the car and you will probably notice the pedal progressively comes up over a period of 2 weeks or so.
Thread Starter
Racer
Joined: Nov 2006
Posts: 380
Likes: 1
From: Janesville Wisconsin
I think the LS7 flywheel is the same as the LS2 flywheel, they were sold in a package.
Im used to the instant engagement, only problem is I dont think its disengaging fully on full throttle shifts. The old clutch that slipped with 166k miles on it shifted as smooth as butter, its harder to go into gear now. Im wondering if there should have been a shim behind the slave ??
Im used to the instant engagement, only problem is I dont think its disengaging fully on full throttle shifts. The old clutch that slipped with 166k miles on it shifted as smooth as butter, its harder to go into gear now. Im wondering if there should have been a shim behind the slave ??
Instructor
Joined: Jul 2005
Posts: 158
Likes: 4
From: Arlington TX
Had mine done about 3500 miles ago. I too have noticed it's a little bit 'toothier' to get into gear at times, compared to the stock clutch...
I didn't notice anything until about 2K miles into the new clutch. More noticeable when cold.
I don't like that. It's not too bad to deal with, but I hope it doesn't get any... toothier.
I didn't notice anything until about 2K miles into the new clutch. More noticeable when cold.
I don't like that. It's not too bad to deal with, but I hope it doesn't get any... toothier.
Burning Brakes
Joined: Sep 2006
Posts: 826
Likes: 69
From: Seoul Korea
Had mine done about 3500 miles ago. I too have noticed it's a little bit 'toothier' to get into gear at times, compared to the stock clutch...
I didn't notice anything until about 2K miles into the new clutch. More noticeable when cold.
I don't like that. It's not too bad to deal with, but I hope it doesn't get any... toothier.
I didn't notice anything until about 2K miles into the new clutch. More noticeable when cold.
I don't like that. It's not too bad to deal with, but I hope it doesn't get any... toothier.
Burning Brakes
Joined: Mar 2008
Posts: 983
Likes: 36
From: Middle Of Kali CA
I think the LS7 flywheel is the same as the LS2 flywheel, they were sold in a package.
Im used to the instant engagement, only problem is I dont think its disengaging fully on full throttle shifts. The old clutch that slipped with 166k miles on it shifted as smooth as butter, its harder to go into gear now. Im wondering if there should have been a shim behind the slave ??
Im used to the instant engagement, only problem is I dont think its disengaging fully on full throttle shifts. The old clutch that slipped with 166k miles on it shifted as smooth as butter, its harder to go into gear now. Im wondering if there should have been a shim behind the slave ??
Premium Supporting Vendor
Joined: Nov 2006
Posts: 30,317
Likes: 165
From: Reading PA
The LS7 flywheel and the Corvette LS2 flywheel are the same. The GTO LS2 flywheel is different and will not work with the LS7 clutch, however. You also may want to check the actual shifter alignment!
Burning Brakes
Joined: Sep 2006
Posts: 826
Likes: 69
From: Seoul Korea
What he said............ he's the man! lol, check alignment?
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
I just put the LS7 clutch into my '99. Yes, it engages real close coming up off the floor. I just assume that there's a lot more meat on it and we know its larger and most likely a stronger spring. I'm guessing it'll wear a little as I drive it and become more normalized.
Le Mans Master
Joined: Dec 2000
Posts: 5,245
Likes: 25
From: Blue Ridge Georgia
I think your answer is in the throw out bearing. I've worked on lots of older Hot Rods and when you start mixing different clutches and pressure plates it's the geometry that's causing the difference. On older Hot Rods if we didn't like the feel of the clutch we would just find a thinner or thicker throw out bearing to make it feel right. But it was easy to drop the tranny and do that. What I don't understand is if the clutch is engaging to quick that says that the there is not enough travel in the throw out bearing, so a thinner bearing would help that. But if your also saying that the shifter feels notchy that could be caused by the pressure plate not fully disengaging the clutch disc. I don't see how you can have both problems at the same time. I would think it would be one or the other.
I just installed a new transmission and clutch and since I don't race my Z I just when with a stock replacement clutch and it feels perfect. These types of problems is why I made that decision.
I just installed a new transmission and clutch and since I don't race my Z I just when with a stock replacement clutch and it feels perfect. These types of problems is why I made that decision.
Last edited by Paul 75 L82; Jan 20, 2011 at 08:03 AM.
