IRONFIST

I have my car at a transmission shop, they replaced the rear main seal, machined the flywheel, put in a new throw out bearing and then they put it all back together..
And then called me to tell me that the clutch "doesn't work"
Which makes no sense, because it worked just fine when I dropped it off.
The clutch won't catch at all until the clutch pedal is completely released, and even then it barely catches, deffinately it's slipping.
Anyone got any ideas?
And yes I did a search and found someone else with a similar issue but didn't get it resolved.
https://ls1tech.com/forums/manual-tr...lp-please.html

25thhawk

iTrader: (3)

Did they check to see if it needed a slave cylinder shim. Prolly does after machining the flywheel.

southpaw0314

iTrader: (5)

I agree with above.
https://ls1tech.com/forums/manual-tr...need-shim.html

Ferocity02

iTrader: (60)

They may have taken WAY too much off the flywheel. Or it has been machined before and machining again made it too thin. You can have them measure it and compare it to acceptable specs.

25thhawk

iTrader: (3)

yeah, you definitely want to measure the thickness of that flywheel. It might not be safe to use depending on how much was taken off of it.

IRONFIST

From what the shop tells me they measured the flywheel before and after and it was 0.012 of a difference. So I don't think that's it...
They did use a brand new GM throw out / slave set up so they insist it did not need any shims.

25thhawk

iTrader: (3)

Well taking that much off the flywheel shouldn't have changed it, but some of the slave cylinders ive seen were upto .125" different in length. So that could be the issue, or you could have had fluid contamination on the clutch from the rear main seal. My bet would be that they didnt measure and you need a slave cylinder shim

SNLPerformance

iTrader: (15)

A slipping clutch that engages at the top of the pedal travel would mean that the slave was over-shimmed or incorrectly installed and the clutch is preloaded. I would be willing to bet something went wrong with the installation in terms of the pressure plate or disc.

Have they given you any updates on the car? Give us a call if you have any other questions.

IRONFIST

Hey Steve, I called you guys yesterday about this...
I'm having nothing but issues and bad luck. My first Monster Stage two clutch got ruined by oil, so then I ordered an LS7 clutch which I now have sitting around doing nothing because right after I ordered it I found a monster clutch for sale in my area so I bought that, finally got it all together again and now this.
I also thought the clutch was preloaded, so I asked if the shop had made sure it removed the entire old throw out bearing, and the shop insisted that the issue wasn't preload but that the new throw out bearing might be "too short". Seemed the opposite to me too...

SPEC-01

iTrader: (2)

I have seen as much as 1/4" difference in OE GM slave cylinder depths, so having a new slave with a different depth than the old one, is certainly possible. The problem you describe would net evidence an issue of lacking a shim or having too much thickness removed from the flywheel...but it could easily evidence a bearing depth that is greater than the original part. As long as the bolts are torqued properly, and the disc is installed in the right orientation there really wouldn't be much they could mess up relative to install.

Ferocity02

iTrader: (60)

I retract my statement that a too thin of a flywheel could cause the clutch to not engage. The opposite would be true. However, if the flywheel has been re-machined before than removed .012 may have made it out of spec. Worth measuring the total thickness IMO, and definitely measure for a shim.

SPEC-01

iTrader: (2)

If the flywheel were machined to thin, or if the car needed a shim, it would cause the pedal to be low...the opposite of what is described. If he had a shim and didn't need it then this could cause the engagement point to be high but there has been no reference from the OP that the car ever had a shim installed.

IRONFIST

The shop is going to pull back the transmission today to take a look, I can't be sure if there's a shim in there from a previous instal as I didn't check, but I will know when the transmission is off. What should I be looking for? What from the previous throw out bearing could have been left behind? A shim? A nut? Could this have caused permanent damage to my pressure plate? And.. of course.. I'll check to make sure the disc is on the right way... I really hope it's not on backwards as that would make it two stage two monster clutch discs ruined in one month

25thhawk

iTrader: (3)

I am sorry, I was thinking backwards. They are right in terms of too much shim. If there sere a shim it would be behind the slave cylinder, but there shouldnt be one. You should check the torque on the pressure plate. I think that if it was torqued too high it could cause the same problem.

Ryan

IRONFIST

Maybe they went with stock torque specs? Instead of the specs that Monster Clutch recommends?

Ferocity02

iTrader: (60)

Improper torque specs would not cause this issue.

IRONFIST

So I took a look at the old throw out / Slave assembly, flipped it over, and saw no bearing there or anything?
Should there not be a plate at the back with a bearing in it?

25thhawk

iTrader: (3)

No, if there is no shim, then there would be nothing. What you should look at is the sticky for measuring for a shim at the top of the manual trans page. Will show you how to measure for one and make sure the clearance is right.

I don't know first hand about the torque spec. I know there was a thread on here a while ago about a clutch that was overtorqued and it moved the pressure plate fingers closer to the slave and he had slippage issues. But I cant say that I experienced it first hand.

Ryan

01whitez

I had my flywheel resurfaced and they gave me a FLYWHEEL shim to make up the difference. I put it all back together and had this same problem. After pulling it back apart and scratching my head I realized my flywheel was too close to the TOB when depressed. This shouldn't cause it to slip though... UNLESS!!! It is protruding far enough out that it actually made contact before the transmission was fully seated, and the techs just snugged it up with the trans bolts. Slim chance but worth a look. Please notice you will not be able to tell if the flywheel is shimmed without removing the flywheel and looking at it. Just an idea. Check you "A to B" measurements that Spec has written up in the stickies, it will give you the answer I am confident!