Well as the title says , the dreadful clutch demon has gotten me. I know there is probably a sticky somewhere but from what I’ve seen there hasn’t been a case exactly like mine. Just got a brand new LS7 OEM clutch installed. When I picked it up from the shop they told me it would be a little soft at first but as I use it the pedal will stiffen up a bit. So I had an hour drive ahead of me and about 10 minutes into the ride I hit the clutch pedal pretty hard and down shifted do to an accident that occurred in front of me. Well the clutch pedal never returned. It only had about two inches of play and I could barely get it to shift in gear. Pedal was very soft with zero resistance, I manually lifted it and pumped the hell out of it and it got a little better. It would stiffen up a little bit and after a few shifts get really soft.

fast forward; I finally get to my destination to get the car tuned and on the first two pulls the clutch was slipping. I contacted the shop and they told me keep on pumping it that the self bleed system in the ls7 clutch will fix itself.. after pumping it up while on the dyno we got 3 good pulls with no slipping, after that it was extra soft again.

tuner then took it around the block with me and the first attempt to rev match the pedal stayed on the floor board again. Rolled to the stop sign where it finally gave out completely, zero resistance in the pedal and unable to get it in any gear while the car is on. What’s your guys insight on this.. here’s a little more info on the car.

2008 Z06
OEM LS7 clutch kit (brand new)
updated OEM master cylinder (clutch)
full bolt on 600HP

 

Sounds like air in the system possibly? Are you sure it had the updated master cylinder with the black reservoir and Dot 4 on the cap?

 

Yupp previous owner had already taken it to the dealership for the recall

 

Two problems I see, and the first is not allowing enough break in time for the clutch to mate in, before you started doing dyno pulls.

As for pedal problems, would dare to guess that you have a leak problem at the slave, or a remote bleeder was installed to the slave and it leaking now instead. Yes, the system will self bleed from the reserve tank, to about the start of the slave itself, but air in the slave is not gong to self bleed out and that air has to be released either from he bleeder valve on the slave, or if remote bleeder was installed, then through it.
Note, that the TB suport race has been burnt to hell on this slave, but shows you the location of the line from the master to the slave on the bottom right, then a remote bleeder atttached to the bleeder vavle port on the top of the slave.


Without remote bleeder,




Bottom line, car needs to go back to the shop to check for a leak problem in the fluid lines.
As for the clutch, with luck, you have not burnt clutch or flywheel up, by not allowing it time to mate in correctly, before you started to throw all the power of the motor at the clutch before break/mate in.

 

[QUOTE=Dano523;1606924926]Two problems I see, and the first is not allowing enough break in time for the clutch to mate in, before you started doing dyno pulls.

As for pedal problems, would dare to guess that you have a leak problem at the slave, or a remote bleeder was installed to the slave and it leaking now instead. Yes, the system will self bleed from the reserve tank, to about the start of the slave itself, but air in the slave is not gong to self bleed out and that air has to be released either from he bleeder valve on the slave, or if remote bleeder was installed, then through it.
Note, that the TB suport race has been burnt to hell on this slave, but shows you the location of the line from the master to the slave on the bottom right, then a remote bleeder atttached to the bleeder vavle port on the top of the slave.


Without remote bleeder,




Bottom line, car needs to go back to the shop to check for a leak problem in the fluid lines.
As for the clutch, with luck, you have not burnt clutch or flywheel up, by not allowing it time to mate in correctly, before you started to throw all the power of the motor at the clutch before break/mate in.

im thinking leak or air in the slave. There is not remote bleeder installed mainly to avoid these kind of issues.. how much time/miles does it take for a clutch to mate ? The issue started soon as I left the shop heading towards the dyno shop. I drove it an hour and a half , 83 miles before it saw the dyno. Car is already back at the shop , waiting to hear back from them today actually.

 

My guess, they did bench bleed the slave and master,, but did not go back to do a final bleed of the slave once it was all back together, to get the last of the air out of the slave. Without a remote bleeder line, need to make a special tool and still a PITA to get to the bleeder valve for the final bleed as well.
https://www.corvetteforum.com/forums...tch-bleed.html

Because of this, want to install a remote bleeder line in the car, and best to go with the Tick remote bleeder, since its bend is placed to not have conflict problems to start with. If they need to pull the Drive line to get to the clutch, would have them install the remote bleeder in the first place.

As for clutch, couple hundred miles of easy stop and go traffic driving, with a lots of gear changes/clutch usages, to allow the friction discs to seat/mate in, before you start to do hard pulls on the clutch.

 

Update !!

mechanic did full bleed this afternoon with a vacuum at the MC. It did absolutely nothing. Clutch is fully engaged at all times and pedal is completely soft with little to no resistance. They want to pull apart the master to check it for failure.

keep in mind the clutch hydraulic system was working perfectly prior to this swap. Previous owner burnt out the McLeod clutch so I did an OEM replacement swap.

 

I hate to say this, but I would wager it's something with the clutch itself (not shimmed properly, missing pilot bearing, defective slave....).

Now is a good time to install a remote bleeder because it sounds like the driveline is coming back down.

 

After digging a little deeper and speaking with the clutch distributor I got some part numbers for what was sent to me. After many google searches on other distributors sites it seems the LUK 04-905 is an “LS7” clutch to fit on Camaros and corvettes (c5) equipped with LS1 and LS6 motors. This clutch also calls for a specific slave.

The clutch for my application C6 (Ls2,LS3,LS7) , seems to be part number LUK 04-216 which also calls for a specific slave (LUK LCS449). However; the distributor did send me the correct Slave for my application. Now I just need to confirm if this is the actual issue I’m having. Seems to be these clutches and slaves are not interchangeable. Anyone with some info on this please chime in as my car is sitting on the lift at the shop.. TIA

 

Disregard update 2 , spoke to a buddy of mine that builds and races corvettes and he said the clutches are virtually the same with the exception of the pilot bearing and slave. And if the wrong pilot bearing was installed it would make a lot of noise and vibration.

so back at square one not knowing what the issue is. Going to check the MS today ..