Clutch and Throw Out Bearing repeat failures

cavalier
chevrolet

#1

Helped my son replace the clutch on his 01 Cavalier 4 cyl. Replaced Clutch as it was slipping, and replaced hydraulic throw out bearing/slave cylinder at same time. New throw out bearing failed after only 500 miles or so, seal broken, started grinding on down shift and coasting (decelleration) followed by leak and no pedal. Replaced with new Slave Cylinder and Throw out bearing, the new one is starting to show same grinding noise on shifting and decelleration. What could cause this? Used the spline alignment tool to adjust the plate on center the right way. Could the pressure plate springs be off center? The flywheel was purple could it be warped and throwing the pressure plate springs off center thereby causing them to rub against the I.D. of the Throw Out Bearing slave cylinder seal? I am very confused.


#2

It could be warped, yes. If the previous clutch was doing a lot of slipping (based on your “purple” description, it was at least overheated somehow), depending on how it was driven, it may have overheaeted and warped it…which could be the source of your current troubles.

You’ll have to rip it apart again, and get it inspected at a machine shop. They can resurface it to remove minor deficiencies, but if it’s warped bad enough to burn up a throw out bearing after 500 miles, then more than likely you’re looking at replacing it.

You could get a second hand flywheel, and have that inspected and resurfaced, then just reassemble the whole thing, replacing the parts that were damaged (which may mean all of them if you cannot determine their condition).

When I’ve assisted in other clutch changes, I’ve noticed they tend to really crank down on the pressure plate bolts, too. That’s not really necessary, as they’re not all that strong, but it’s a good idea to use a torque wrench and a dab of locktite. If a bolt (or more) has broken or come loose, that could cause a similar issue.

Good luck,
Chase


#3

Chase,

Thank you for the reply. I was afraid someone might say that. This will be the fourth time taking it apart and putting back together!! what a pain. I will check on the torque specs for the Pressure Plate as well. Is there a way to measure the inside diameter of the PP springs for run-out by rotating the engine and using a test indicator? to see if that really is the problem? Would we need to take all the spark plugs out so that the engine could rotate freely without building up compression in the cylinders?


#4

Sometimes “Parts Store” parts are not compatible with one another. The term “Rebuilt” has become meaningless. I would use new factory parts and check carefully to be sure you are assembling them correctly…


#5

I’m sure you could construct something to measure it, but not sure that it wouldn’t be time or cost prohibitive.

Flywheels don’t normally go bad without something being done to them. Follw Caddyman’s advice, and get a factory part. Failing that, you could check the local yards. I’ve seen plenty of Cavaliers in the yards around me.

I’m all about saving the odd dollar (or hundreds or thaousands) by re-using parts that others can’t. Since you’re now such an experienced tranmission-ripper-outer, you should be able to get at one with little problems. :slight_smile:

Check the main bolts, too (flywheel to crankshaft). Some (not all) are a one-time use bolts. You don’t want that particular failure staring at you later.


#6

I am assuming by one-time-use you mean a “torque to spec” bolt which elongates at a particular torque and is no good after that. I hear they are a pain and sometimes break off if you try to re-use them. Thanks for the warning. Yes, we have both become good ripper-outers and have it down to less than 2 hours with limited tools so I guess not too bad!. Will check on flywheel price both new and at yards as well as taking it to a machine shop to be re-surfaced, but if it is terribly warped won’t bother.


#7

No idea without car in hand, but you’re missing something on the installation. The purple flywheel is caused by a badly slipping clutch and if you’re continuing to replace the clutch discs with a purple (yes, it’s likely warped) flywheel then it’s time to resurface or replace the flywheel for starters because a new disc likely won’t last long with a warped flywheel.

How old is your son and what are his driving habits like with a manual transmission? Not running around with his foot partially depressing the pedal all the time is he?


#8

He is 21 and his driving habits used to be worse, thus the bad clutch, but he is now growing out of that stage. The new clutch plate and pressure plate have only been in for 600 miles so far and they are still good, but the TO bearings keep failing, so I am assuming it is the fault of the previously warped flywheel causing the Pressure Plate to be off-center thereby causing rubbing on the ID of the TO Bearing when clutch depressed and then ultimately failure of the TO bearings. Can’t think of any other reason and just wanted opinions before we go and tear it out yet again.


#9

The clutch seems to be partially released; slipping is a better description. Thats why the flywheel is purple. There could be an adjustment. It may be possible to shorten the push rod on the clutch master cylinder or on the slave cylinder.

Then there are washers or spacers that might have been left out. I doubt that last statement I made. If there are no adjustments you might have to adapt a home remedy.


#10

No adjustments available in this system. Fully hydraulic. No washers left out. The purple flywheel is from the original clutch, not the new one. We replaced clutch plate, Pressure plate, slave cylinder-TO Bearing assembly (comes as one assembled unit), but did not re-surface flywheel. New TO Bearing failed almost immediately. Replaced that TO Bearing, second TO Bearing failed after about 500 miles but started to make noise before the seal broke, replaced it. Third TO Bearing is currently in the system, it is starting to make noise, but not yet failed, but fear it will shortly. Assuming the only thing left to do is take it all apart again, remove the flywheel, inspect for warpage, have it re-surfaced or replace it and while we are at it replace the current (third) TO Bearing with a new one because it is probably damaged already.


#11

Point being is that if the throw bearing is spinning all the time with pressure applied to it for whatever reason (foot on the pedal, installation problem, fitment problem, etc) the grease in the throwout bearing can overheat and start cooking. The bearing will not last that long when the grease goes south.

The purple flywheel is due to clutch disc slippage and that also falls back on the reasons for the throwout bearing failure.
I’d make sure that he’s not driving around with his foot on the clutch pedal all the time.


#12

Thinking on it a bit more, there’s most likely a glaze on it, anyway, and once it gets heated up to that point, it’s going to slip even more.

I’ve seen instances where the throw out arm isn’t put back on correctly, and causes slippage. Just one more thing to check. :slight_smile:

Good luck…
Chase


#13

Sometimes there’s a little inspection window (or a small piece of plastic you can remove to create an inspection window) on the transmission. if there isn’t one, can you see in through the slot where the throw out arm enters the bell housing?

Once you’ve got it together, use that little window to verify there is clearance between the throw out bearing and the pressure plate. If you can safely do it, run it in neutral and see if the bearing is pressing on the pressure plate. If you can’t do it safely, then don’t try.

Verify the springs are A) there, and B) holding the bearing to the arm, too. If they’re not, the bearing can just sit up against the pressure plate. That would cause it to fail, too.


#14

Was the friction surface on the pressure plate cleaned? They are usually coated with a shellac to prevent rust while on the shelf. And If the flywheel has not perceptible grooves a few passes with an 80 grit disc has always done an adequate clean up. Failure to clean up the pressure plate or flywheel can result in the clutch chattering severely and often results in the driver slipping the clutch excessively in an effort to get a smooth take off.


#15

This is a WAG possibility. I disassembled a Cavalier manual transmission where the input shaft retention nut had worked loose. The resultant motion of the input shaft back and forth took out the slave cylinder which caused a no shift condition.

So the next time you have the transmission out, take off the cover of the bearings (side away from the clutch splines) and see if that retention nut has come loose.

Let us know what you find that solves this problem.