This will be the third through out bearing in (6 months/7500 miles). The original one went 115K and never made a noise. I had a pressure plate failure so I changed out the clutch/pressure plate/ TB & slave and pilots bearing (Monster stage 2 with 18lb flywheel and supplied TB & slave) the pilot bearing failed ( I'm guessing I damaged it when installing driveline), but it did go for 5k and many track days). I went back in and change out the Pilot (with a bushing type be cause of some minor gulling on the input nose) and also change out the flywheel/clutch. I didn't go stock with the intention to lighten the rotating mass. That was not the case as the Monster pressure plate was much heaver then the stock. The new clutch is a twin disk MC RST and Alum flywheel,(that combo is just what I wanted) with a new TB, Pilot Bushing style bearing. With in 2k the TB failed. Last week I replaced TB with a GM part (just like the original) and for good measure the Pilot bearing. Now less then 500 miles the TB is making noise... It's not that I don't enjoy the removal of the driveline (that's getting easy) but this TB thing is getting old.

Any suggestions ? Thanks

Mark

 

Well,,,,,,,,,,,, HERE IS WHAT I KNOW ON THE SUBJECT!


When you install other than OEM GM clutch parts, the stack up height of the parts can be different enough to have an adverse effect on clutch parts and proper operation.

When you installed your clutch, have you ever taken the CRITICAL MEASUREMENTS that will insure that you have the PROPER AIR GAP between the Throw Out Bearing and the Pressure Plate Fingers???

My guess is that you have insufficient clearance between the throw out bearing and the pressure plate fingers and the throw out bearing is ALWAYS rotating under pressure.

Some clutch manufactures specify that a SHIM needs to be installed behind the SLAVE CYLINDER.

Taking the critical measurements will let you know if you need a shim and if you do how thick it needs to be...

When you don't have ENOUGH CLEARANCE between the TOB and the Pressure plate, too much shim is in place OR something is incompatible.

QUESTION?

1. Do or did you use any shim/s behind the slave cylinder.

2. What was the critical measurement clearance measurement?

3. If you put the car on a FLAT LEVEL HARD SURFACE, In 1st gear and REV the engine to 5-6K RPM, DOES THE CAR MOVE FROWARD?


Bill

 

I did all of the above, stock GM part, it has a pre-load spring with constant contact with the TB. I do not get any creep with the GM part, but did with the Monster/unknown TB brand. (and it was different at the bearing contact point). I talked to with the clutch manufacture they confirmed that my numbers were with in spec.

It's possible that there may be to much play in the pilot bearing, allowing the the torque tube mane vibrate...

Thanks Bill.

Mark

 

Have you inspected the couplers inside the torque tube? I lost a factory clutch and damaged a street twin due to worn out couplers.

 

Maybe a stupid question... but, did any of the three bad TB show or have any evidence of what might be the cause of failure? You still have them by chance to inspect them and get a clue?
What brand were the other TBs?

 

does the noise go away when you press the clutch pedal?... does it go away as rpms increase?... it might be clutch chatter and not the throwout bearing, unless you have more evidence/info that is actually the cause... aluminum flywheels are also bad about warping when heated up and this could cause some unwanted noise/vibration, just throwing some ideas out there

 

I do have the old TB's. and both are (AutoZone, Napa type) One came with the Monster clutch package. The both show slop and dry bearings. The new TB is GM HP part, and was much tighter bearing, and matches the Original TB. I have inspected the Torque Tube, and there is no bearing play and damping couplers are in good condition. My guess is that I may have damaged the pilot bearing. By the way, the noise was the same with both clutches so I'll rule out the clutch it self.

Thanks to all,

I'll update later when I pull it apart again this week.

Mark

 

Chalk up the problem to the pilot (bushing) and damaged input nose. It's getting easy to remove the drive-line. I'm going to find a friend to help reinstall the drive-line this time or maybe just install the torque tube then the trans. Any one ever done it that way?

Mark

 

I always do it that way... I work alone most of the time and it's too much of a pain for me to get it all in as one piece... with the torque tube separated from the trans/diff I can get under the car and wrestle with it and then install everything else behind it... there's also less chance of damaging the pilot bearing and pressure plate fingers since there isn't so much weight behind it and is much easier to maneuver into place rather than measuring a bunch of angles, heights, and whatnot that some do when reinstalling the drivetrain

 

I do it that way by myself also... Much easier and less probe to damaging the pilot bearing and bending the clutch disk.

REMEMBER,,, Its apart. I highly recommend MEASURING the critical clearances!!

You also stated that you used a solid pilot bearing /bushing. Most of the people who repair the drivetrain for a living recommend against the BUSHINGS. Use a OEM Pilot bearing.

Bill

 

Thanks Bill,

The input nose is damage and it was the recommendation that I use a bushing. I'll be going back to the OEM pilot when the new input arrives.

Mark

 

To confirm you are currently running a gm slave or a autozone/napa?

 

You can do it that way. RPM actually recommends installing the torque tube empty, then insert the prop shaft.

https://www.corvetteforum.com/forums...post1580534401

 

that's actually a pretty good idea, I never thought of that

 

GM Slave, same part # as OE.


Mark.

 

To me the two things that a back yard mechanic needs to know is 1) how to install a cam in a SBC and 2) clutch geometry.