Clutch won't disengage

[Pranav]

Is there a trick to bleeding the ls1/t56 master/slave cylinder? We installed the whole setup with a remote bleeder. Before trans install we checked the bell housing measurements and found the clutch slave didn't need any shimming so we installed it and I sent the clutch shim kit back. Just running a stock pressure plate. Running the stock slave and master, but made my own 3an line and used the roll pin 3an fittings.

Pumped and bled it a million times, clutch won't disengage at all. On jack stands with clutch in the rear tires will spin as soon as I put it in gear without lifting clutch. Can't even get it into the higher gears.

Bought a mityvac and put the hose into the reservoir and pulled 25" of vacuum, got a decent amount of bubbles.

Still won't disengage. Went at it again a few more times with the mityvac and I still am getting a few tiny bubbles as I pump the pedal out the top, but I'm not sure if that is just the high vacuum slipping air past some of the seals.

Bleeding again out the bottom I am no longer seeing any air.

[Pranav]

I've pre-emptively ordered a new LUK MC/Slave combo because I'd always intended on keeping a spare set.

Towards the end of last night's work I did suck up a little bit of rubber with the vacuum.
Couple that and this thread I may have messed up the MC with too much vacuum or something:

http://ls1tech.com/forums/manual-transmiss...hy-shiftin.html

Going to try run a lower amount of vacuum first as I'm reading that 25" can start pulling air in and causing more problems. Also hearing a squishing noise from the MC area when I push in the pedal, not sure if the MC is messed up; will be back Thursday to take a closer look.

[Supercharged111]

Ditch the stock junk and go wit a Tick MC. My Z06 gave me all sorts of hell even with brand new GM master/slave.

http://www.tickperformance.com/1998-2002-ls1-camaro-firebird-18/

[GlennCMC70]

Did you ever just try and let it gravity bleed? That is how I did all my LS stuff.

[Pranav]

I will try again, I think I did gravity initially but went straight to pumping.

Is the LS1 clutch supposed to feel any different than the LT1? I remember the LT1 being smooth and light; on the LS1 it felt the same when I gravity bled it and pumped it a little, now it's all mushy and firm at the same time, it almost feels bad trying to hold it to the floor.

[dtanker65]

I spoke with tech support at Ram and was told the slave cylinder needs .600 preload and .400-.450 travel.

[Pranav]

One thing I just realized, I ran 12" remote bleeder hose and zip tied it down to the lower part of the trans; with the bleeder outlet being so low I may still be trapping air in the slave. I'll let it loose and hang it high when I try a regular bleed tomorrow.

[GlennCMC70]

That will trap air. Most people run it up to the firewall.
What in the set-up is not stock other than the bleeder?

[Pranav]

Running OE/stock MC and Slave .

What isn't stock about it is the remote bleeder and the 3AN pressure line I made myself. I had to replace the fittings on the MC and Slave with some russell 3an fittings to do this.

The clutch pressure plate and flywheel are "stock" as well from rockauto.

[GlennCMC70]

No shimming should be needed then.
The trans will not seat all the way unless the pressure line is connected. This indicates there is some preload built into the system.
All this is out the window if there is air in the system.
Get that bleed line up and crack it open and let the air out.
You can also open the bleed, press the pedal and with it pressed, close the bleed. Then release the pedal. Be sure the fluid is 100% topped off. Don't want to suck air in from the top.

[Pranav]

Yeah I bet it's that bleed line/screw being below the trans is traping a big air bubble. I recall now why all caliper bleed screws are above the calipers.

Should be back in the garage tomorrow night to try.

BTW in case anyone is wondering, LUK = OEM. Both made by AP and have the AP logo; LUK slave is $38, GM OEM is $130, same damn thing as far as I can tell. Same goes for the master cylinders.

[Pranav]

Long story short, bleeding and lifting the bleeder didn't work. Pulled the trans and found my slave cylinder was messed up; it wouldn't go in all the way by 1/4" which threw off the slave shim measurements compared to the replacement slave. Even though I'm running a stock PP my ACT disc must be thicker than stock, since I now need a 0.15" shim as opposed to thinking I needed no shim previously.

Thanks to Glenn I have some on the way, hopefully get the trans back in and it should work this time.

[dtanker65]

A tip Jason Massey shared with me was to bench bleed the slave and to zip tie a plastic bag with a paper towel inside on the end of the hose to keep fluid from spraying when the slave preloads. I haven't had to bleed the clutch doing this. Don't forget longer bolts when using a shim.

[Pranav]

Fixed!

Installed a .15" slave shim (Thanks Glenn) and put it in, rebled it all. Pedal felt better but it still wasn't disengaging. However, I could start it clutch in but dragging in 1st gear as opposed to 3rd/4th previously so there was some progress.

I swapped in a RAM adjustable master cylinder, which is nothing more than a stock LUK/GM master cylinder with the push rod modified to take a threaded heim joint. Set it to hit the pedal stop just shy of the cylinder's internal stop and bled it. I noticed it took only 6 pumps to empty the reservoir vs 9-10 on the original one; however on the original one I recall also did do 6 pumps at some point initially, so maybe I did mess it up with all of the pumping and vacuum, who knows.

Anyways it seems to work great right now; I'll have it run through all the gears on the dyno to make sure I don't have any problems up high but I think I should be good.

Now to scramble to get all the loose ends tied up on the car and get this thing tested.

[BryanL]

Good deal. But why are you running an ACT Clutch disc?