04BlackGmc

iTrader: (19)

Little story behind the issue.
Car is a LS1 swapped 240 with a t-56. Brand new OEM GM Slave cylinder, (used under 500 miles mcleod Super street pro clutch) out of a LS1 fbody. Willwood 3/4 master cylinder (sikky swap kit) Put around 100 miles on the car in one day sat for 4 hours in the middle of it and took it back out later no issues. Go to get in the car the next night and the clutch will not dis engage, Try to put it in gear and the car pulls itself forward very slowly but will not fully go into gear. Bleed it at the master and remote bleeder many times no air in the system and seems to be good pressure. Pulled the trans today to try and figure out what is going on, clutch disc/pressure plate were checked for proper torque(trans just installed a few weeks ago by a friend and i at my house) clutch disc and pressure plate were good and torque was correct.

Removed them both to check flywheel still torqued and nothing looked off at all.
Last time when we put the trans in we measured to see if a shim was needed(none was needed). The slave from what we can remember was not bottomed out like the picture i will attach below.



From what i have seen online they are not bottomed out like this and B measurement is 1.875 but from what ive seen it should be 2.0xx.
Is it possible the slave movement has changed? or Slave is bad? i'm at a loss here and any input or help would be great.

gconnoyer

iTrader: (1)

Fwiw, the A measurement was 2.375 and the B measurement (with the slave fully seated like this) was 1.875. So a total differnce of .500

We didnt put the car back together yet but going off of Mcleod's recommendation for their clutches (.100-.300) we need .300 shim to get it in the middle of their range.

As long as the slave is ok seated this far down, then all we need to do is get .300 total worth of shims and it should be good....

Any thoughts on this, mainly just the slave.

redbird555

iTrader: (14)

well when you measure the slave for a shim you have to have it bottomed out like the however you also need to have the throwout bearing on it seeing as the the top of the TOB is what makes contact with the pressure plate not that plastic so just reinstall the TOB with no spring and measure again.

gconnoyer

iTrader: (1)

Right thats how we measured.
The picture above and the main thing in question right now is how far down the plastic piece on the slave is supposed to be when its bottomed out

redbird555

iTrader: (14)

how are you take taking your b measurement? I have my tranny out now and if i just measure the slave from its base to the top of the TOB without the spring i too get 1.875 or there about however you have to take this measurement when it is bolted to the transmission and measure from the transmission face to the end of the tob that should give you a better measurement

04BlackGmc

iTrader: (19)

The weird thing to me how everything was fine for 100 miles one day and then the next the clutch will not dis engage. This is the part that stumps me.

redbird555

iTrader: (14)

since it was working at first then you shouldn't magically need a shim it would have been noticeable from the start. the slave in the pic is bottomed out correctly so if your is bolted up and bottomed out like that then yes its fine. since you lost you pedal so to speak over night i'd say the slave or master has an internal leak that wont allow it to hold pressure over time.

I had a similar issue, mine would get bled and be great until it sat overnight then the clutch pedal would go lip and i'd have to pump it back to build pressure. ended up my brand new m/c was bad now since you already have a good mc maybe the slave is messed up, but i would also check the mc to be safe.

Tonya

iTrader: (1)

Both the slave and MC are new. This is my car we're talking about. The pedal hasn't lost pressure at all. And there are no visible leaks anywhere. It didn't makes sense to us either that at first it didn't need a shim and now it does.