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I've read over 100 posts about this LS7 business, and tried pretty much tried every tip besides removing the trans...I disconnected the quick connect from MC to Slave and swapped my stock connector onto the end of the LS7 slave hose...the Clutch install was done correctly without a spacer and the pedal pumped back up in a matter of 3 cracks of the remote bleeder, and worked flawlessly for about 200 miles...I had to change the cam reluctor to a 4x (LS2 swap) so my Lingenfelter TRG-002 could convert it and PCM could read it...after I got that all buttoned up, I ran the car to take it for a test drive and didn't have a pedal anymore...Mityvaced it, traditonally bled it, brought it to a shop so they could bleed it, and NOTHING! I towed it back to my house and the pedal was rock hard...diconnected the quick connect to release pressure, and now I'm back to no pedal..it pushes fluid fine, but won't pump up at all..before I go pulling the trans apart, is there anything else I can check?
...the Clutch install was done correctly without a spacer...
Assuming you swapped to an LS7 slave... I'm curious what your measurements were when you determined you didn't need a shim.
Per Tick's site:
How to determine if a shim is needed for your setup:
During each and every clutch install you perform on a newer GM vehicle, you must measure to see if a shim is necessary for proper installation. This is done by taking two simple measurements (see worksheet):
1) Measurement "A" is the distance between the surface of the bellhousing that meets the transmission to the tip of the pressure plate fingers. To get an accurate measurement, the clutch must be torqued properly.
2) Measurement "B" is the distance between the throwout bearing surface to the transmission surface that meets the bellhousing. To get an accurate measurement, the slave spring must be removed and the bearing must be fully seated at the bottom of it's travel; resting on the slave's base.
Once you've got your two measurements, make sure that measurement "B" is ~3/16" to 1/8" LESS than measurement "A". If you come up with more than 1/8", add an appropriately sized shim between the slave cylinder and the transmission in order to get the measurements where they need to be.
Your “A minus B” measurement should be 0.125 to 0.200 for adequate bearing travel and to allow for clutch wear. If there is no difference between the two measurements, or if "B" is greater than "A", there could be a problem with clutch engagement which could result in premature clutch slip and eventually a total failure. Contact your clutch manufacturer before proceeding with the install.
I'm just throwing a dart here, and it sounds like your issues are more hydraulics-related, but I thought I would mention it anyway. Perhaps if the "gap" measured above is too great, you could have a "no pedal" issue? But then I don't know how you got a few hundred miles of trouble-free driving if that was the case.
I was looking at a couple more write ups last night and saw the debate on shim vs. no shim, when I pull the trans out to inspect, you bet I'll be making a couple measurements...I went with no shim figuring I have an LS7 slave as well (complete Luk kit) and shouldn't need one..I'm perplexed on how it was perfect with perfect shift for those miles..The more I think about it, the more I realized I'll be on my back pullin it and completely reinstalling it starting tomorrow if I don't get that pedal back by today...
The shim thing is definitely a contentious topic; but it seems just about everything to do with a clutch swap (or any mod, for that fact) with this car is. But that's the name of the game when you're swapping parts into a car that aren't made specifically for that car. Hence, "mod hell".
Don't get me wrong here, I'm not a mechanic or an expert by ANY stretch of the imagination. But I'm fairly "handy" and I've enjoyed doing most of my own work on my cars since I've owned one. I went through the LS7 clutch swap and all of its nuances last year, so I do have at least some experiences to offer/share. When it comes to the clutch system (hydraulics included), I think it can be simply summed up to say that every V1 out there has variences in how things have aged as well as how they operated right from the factory. It would seeem that some hydraulic systems perform beyond expectations with tons miles on them, where others under-perform even with the lowest of mileages on them. Hence, you see a lot of different opinions and experiences regarding the need for things like slave shims, replacement master cylinders, so on, and so fourth. In my experience, it's just a matter of keeping an open mind and listening to all the help that's out there (here), and having to go through some trial and error until you get things right.
One thing's for sure: You should definitely perform those measurements I quoted above when you drop the trans again. Be careful to follow the instructions carefully, as you don't want to wind up with the wrong measurement like I did (ooops). You'd probably also benefit from bench testing your slave too. And while you're in there, you might want to make sure that your pressure plate bolts aren't over-torqued. I think 48-52 ft lbs was the happy place for those. Put a dab of loc-tite on the bolts if you're worried about them not being tight enough.
Off the top of my head, that's about all the wisdom I can think of that I learned from my experience. Hope it helps.
So after this post I pulled the tranny and saw a horrible sight and wanted to share what I found...the slave/throw out pushed the Pressure Plate fingers into the clutch disk, how this happened I don't know
I can't remember when I did mine but can the disc be flipped maybe it is in the wrong way and the other side has a shorter part so the fingers can't catch it. I personally did not have any issues with using the LS7 slave. It was close to the floor when it was first installed but is in the middle now and has been working great for many miles.
The disc is clearly marked flywheel on the flywheel side, I haven't seperated them as of yet, kinda waiting to see what happens with the claim..that's the first thing I looked at when I took it out...why the trans side is raised higher I don't know...I looked at my stock disc and tried to flip it the other way and it wouldn't even fit..I'm guessing it was a flaw that didn't get caught in quality control.
Just a guess here but the ls7 pressure plate is "self adjusting". Could be something let go in that aspect.
I do know i blew a slave and pulled the trans to swap it out... When i got it all back together again the clutch dragged like hell. I had to pull the trans and pressure plate then reinstall for it to reset the clutch height. Food for thought
Crazy...this really boggled my mind, and my buddy thought it was strange as well, he's been turning wrenches for 35 yrs and has never seen this happen before...but that pressure plate thing has me curious now...hmmm
To get an accurate measurement, the slave spring must be removed and the bearing must be fully seated at the bottom of it's travel; resting on the slave's base.
What does it means, is it truly necessary to remove the spring from the slave for measurement or make it the job of measuring a lot of easier without installed spring?
I read something about a second person who will help during measuring to fix the throwout bearing on it`s stop position at the bottom from slave...
I disconnected the green boot on the slave to see the full spring and then i put the throwout bearing to itīs maximum backwards position as the stop cames, but the spring wasnīt completely pressed in this position, so iīm curios about this action, if itīs truly necessary to find the measurement "B" and bec the spring canīt leave her position there on a normal way, i have to force her and that isnīt a good idea i think on such a fragile peace of plastic or whatever it is, someone can follow me?!
Best regards,
Ronald
Last edited by Choppy_Idle; 07-17-2015 at 04:21 PM.
07-03-2015, 03:57 PM
pedal loss after LS7 kit install 
