The Stovebolt Site Forums The Shop Area Engine Shop Clutch Disc Life?

I'm curious as to what would be the normal life of a clutch disc? No popping the clutch or pealing rubber allowed. Lets say usage is, for an example, no more than 5,000 miles per year. Any guesses out there?

I ask because I just pulled "Lucille's" clutch, date stamped 2/28/95 and rebuilt in Canada, and the thickness of the clutch disc is just .023" thinner than the new clutch disc I bought from JC. Wouldn't one believe that this truck has not gone far since 1995?

A clutch disc life naturally depends on the driver & type of use. We used to have school buses that would wear a clutch out in a month. On These old trucks the lining will last indefinitly. Something else will go bad with the clutch before you will wear it out. Back when this stuff was used every day,all day about 50-75 thousand miles was the norm.

Wrenchbender Ret:

You said, "Something else will go bad with the clutch before you will wear it out." I assume you mean something other than the disc will wear out first? What would that be?

The t.O. brg. can wear out. The pressure plate spring or pivot can break. Sometimes one of the springs in the disc breaks out & locks up the clutch so it won't release. Some reman pressure plates run out of travel before the disc is wore out. The collar on the trans. front brg. retainer can break. The pilot bushing or brg. can wear out & cause rough engagement. Oil leaks can get oil on the linings & cause chatter & slipping. So you see, clutch failure is not always just worn out linings.

Wrenchbender George,

Well, the throw out bearing was definately shot!! AND, it left a thick gunky coating of grease inside and outside of the clutch pressure plate housing assembly. I bought a new T.O. bearing. I've also disassembled the pressure plate from the housing for cleaning of all the parts of grease and discovered that the "O" markings on both the pressure plate and housing didn't line up!! Someone had assembled it incorrectly! Of coarse, the old clutch disc is also coated with a light film of grease. I'm surprised it wasn't chattering severely. It really could still be used but I'm installing a new one.

Also, as I look up into the inside of the bell housing it too is all greasey. Gotta clean up that mess! Both the flywheel and pressure plate working surfaces are in very good condition. That I'm pleased about!

I'll be cleaning out as much grease as I can and then reinstall the clutch with the aid of that tool you send me!

Oh, I didn't see any signs of broken springs anywhere. And the tranny front bearing retainer is in excellent condition.

In the end I think my biggest problem was that T.O. bearing!! Why it wasn't replaced in '95 I'll never know. I just hope the new one lasts a long time. The second biggest problem was leaking tranny seals which left a coating of oil all over everything near it.

With any luck I should be good to go for a long time now! Don't know if I can put 50-75,000 miles on "Lucille". Time is running out unless I take her on one hell of a road trip!!!

I think they can last a very long time, or no time at all, it depends on the use and the driver.
In my 1 ton with low gears I would imagine the clutch still looks near new after about 10,000 miles because you don't need to slip the clutch hardly at all to get moving.
In a truck with tall gears and or a poor first gear ratio a clutch disc may not last as long.

Not a Stovebolt, but I had a 95 VW with 235,000 miles on the original clutch, no signs of weakness or slippage. Then a "friend" borrowed the car for one evening and ruined the clutch. Obviously it was not far away from happening any how, but I bet there was another 10 to 30 thousand miles in it if I hadn't had any "help"..

The operator makes a big, probably the biggest, difference in clutch life.

Grigg

Had a 72 chev,the clutch would go out every 6 month's before i bought the truck.I had to help my friend put in the new ones all the time.I couldn't convince him to get the flywheel turned until the last time we did it.Then he sold me the truck and said rember it'll need a clutch in 6 month's!!I drove it 5 years,never had a problem.Just make sure the surfaces are squared up and it should last a heck of a long time depending on driveing habit's.I've seen other veichiel's that can't hold a clutch but the people don't know how to drive em either.Tom

I have a '46 Chev 1/2 ton that had a rebuilt '54 235 put in it along with an NOS heavy duty "gear jammer" 4 speed in 1986. This is the no synchro transmission that requires double clutching at every gear change. At the same time I went to the larger "heavy duty" clutch. This truck is driven about 2000-2500 miles per year. The entire arrangement is still in service. Clutch chatters a bit when the truck is cold, but smooths out completely once it's warmed up. Oh yeah, not doing any burnouts -
(couldn't if I wanted to). Yes, you read that right - I've run it about 55,000 miles since the rebuild.

David Bush

I've changed out a bunch of clutches over the years and most times it was to replace a throw-out bearing that had started to squall. Too much left foot resting on the clutch pedal!!! Have always added a new disc just as a precaution. If the flywheel has "blue spots" on it you know there was some heavy usage but never saw one that was totally burned out on a street vehicle.

I've noticed the trend to couple a new replacement disc to a new pressure plate and T/O bearing. Really drives the price up a bunch and unless you spring for a flywheel cleanup, is sorta like putting on clean clothes without a shower!!! Ain't progress great?

Dave

Back before automatic transmissions came into general use, the family shop had a maintenance contract with a local taxi company. These cars got the "hot seat" treatment, where two drivers shared the same car, each with a 12-hour shift. A good brake job would last an average of 6 weeks, and depending on the ability of the driver team, a clutch might go 3 to 6 months. We also maintained a fleet of 1-ton chassis step vans for a bakery. A delivery driver burned out a clutch on his morning run. It was towed to our shop, we replaced the clutch, and he burned out another one on the afternoon delivery route! His supervisor had an unusual request- - - - -"Get that clutch out of there while it's still nice and hot- - - -I'm gonna make him sit on it!" Yep, that was his first and last day on the job as a deliveryman!
Jerry