Slipping Clutch

[ChrisMinelli]

Hello,

 

I drove my car today 140 miles round trip while working — very cool and I finally got to cruise a bit.  However the clutch started slipping about 100 miles into the trip.  It’s never done that before.  I am assuming it needs to be replaced (as far as I know it could be decades old) but before I look into how to do that I thought I would ask to see if there is any other, less extensive thing I should be checking?  52 Plymouth, 3 on the tree.  Original transmission if it matters. Thanks!

[keithb7]

Congrats on driving your car! Sorry I can't come up with much else when clutch starts slipping. Pressure plate springs get weaker. Clutch disc gets thinner as it wears. Combined, it adds up to less pressure to hold things together.

 

On this list of things to consider are a clutch and pressure plate. Throw out bearing too. New front mounting gasket for the tranny to bell housing. A clutch alignment tool. While the tranny is out, hows it sealed up? Ok? Park brake lining working well? 

[Sam Buchanan]

Do you still have free-play in the clutch pedal? Anything restricting the pedal preventing it from returning all the way?

Edited May 13, 2020 by Sam Buchanan

[kencombs]

Check the items Sam mentioned.  If the throwout bearing is touching the release fingers due to lack of free play or binding that will cause it to slip.

 

Otherwise, time to pull the trans, clutch, pressure plate and throwout bearing. 

[plymouthcranbrook]

51 minutes ago, kencombs said:

Check the items Sam mentioned.  If the throwout bearing is touching the release fingers due to lack of free play or binding that will cause it to slip.

 

Otherwise, time to pull the trans, clutch, pressure plate and throwout bearing. 

Don't forget the pilot bearing in the flywheel.

[keithb7]

I am curious, what are the symptoms of a worn pilot bushing? Tranny pinion slight misalignment problems? Hmm...

Edited May 13, 2020 by keithb7

[ChrisMinelli]

Keith -- thanks!  It was great to get the car on the road but (of course) with these old cars something is always breaking.

 

I did some more diagnosis this evening: I get a grinding and whining noise whenever the car is running and the clutch is depressed.  I also can't shift gears at all when the car is running.  Trying to shift makes a terrible grinding sound and I can feel strong vibrations in the shift knob and the clutch pedal.  In order to get the car back into the garage for the night I had to turn off the engine; shift into reverse; and then start the engine to back up the car.  This is significantly worse than it was this afternoon.

 

So probably my next move is to check the pedal itself to see if it is binding; otherwise I am assuming I'll be dropping the transmission and getting very acquainted with old Mopar engineering while my wife and kid get irritated I'm taking up the entire garage for the summer.

 

[Dartgame]

Sounds like a failing throw out bearing. Check the clutch fork for the specified free play, before doing anything more. It may just be out of adjustment.

 

Assuming the worst. When you get the trans out, check its shift function, if it seems okay then leave it. If not, a rebuild might be in order. If you've never rebuilt a manual trans,  these three speeds are about as simple as it gets. You'll need a rebuild kit including bearings synchro and other gaskets as well.

[plymouthcranbrook]

And take some advice from some who have learned the hard way. If you have to remove the trans for clutch work replace everything related to the clutch.  When I was younger I pulled a New Process 4 speed out of a 66 Plymouth because the   throw out bearing  was making nasty noises.  Two months later had to do it again because the rest of the clutch failed.

[Eneto-55]

1 hour ago, plymouthcranbrook said:

And take some advice from some who have learned the hard way. If you have to remove the trans for clutch work replace everything related to the clutch.  When I was younger I pulled a New Process 4 speed out of a 66 Plymouth because the   throw out bearing  was making nasty noises.  Two months later had to do it again because the rest of the clutch failed.

I concur.  On the first engine swap I was involved with where I was the one responsible to see that it all worked in the end (doing it for my college roommate, who did not have much experience with auto mechanics), we had difficulty getting the transmission to seat properly - even with guide bolts & a stabbing shaft.  Turned out that the clutch pressure plate was weak, and not holding the clutch plate in place, and it would easily get knocked off to the side when we started the pilot shaft in through it.  AND, he had to replace it pretty soon after we got the car back together.  (I won't mention what kind of car it was, because it was one of those "other" ones.)

[ChrisMinelli]

Thanks for the advice!

 

A quick question / thought I just had -- I'm a hobbyist at best and will be learning this all as I go.  If it takes me a few months to do this, is there anything I need to do with the rest of the car to keep it from deteriorating?  Can the engine be started to idle while the transmission is out, to keep things flowing?  Are the brakes and cylinders I just put in (new) going to leak and have problems from non-use? 

[keithb7]

Engine and brakes will be fine sitting for a few months. If the brake cylinders leak, its not because they sat for a few months. I assume they have brand new brake fluid sitting in them?

 

I too am a rookie at this. I bought my first old Mopar 3 years ago. My second old Mopar 1 year ago. I’m in the same boat as you, only about 3 years ahead of you. 
 

The comments that were made above, about doing everything right the first time are sound. However I still don’t throw all new parts in when I go into a system.  I like to understand why and how various parts and systems work together. Trouble shooting along the way will make you a much better mechanic than just being a parts swapper. 
 

Yes I was into my tranny and clutch over the last winter. Yes I am back in there again now. Making things better. Doing things that I did not know back in Dec. An example is sealing up the transmission counter shaft end. That’s not in the original manual that I own. If you don’t know to ask, you miss out and plow ahead. 
 

Additionally I’m not overly excited about quickly dumping $15K into a car that would likely net me $10K or less when I’m done. So I do what I can to clean up and salvage parts. Reusing them along the way. 
 

I truly enjoy working on these old cars. I crave the new knowledge and experience. I had fun pulling the tranny again last night. It does not bother me that I was in it in Dec and now again.  Your motivation and thought process may be different than mine. Enjoy whatever path you choose to take. 

 

[Sam Buchanan]

1 hour ago, ChrisMinelli said:

Thanks for the advice!

 

A quick question / thought I just had -- I'm a hobbyist at best and will be learning this all as I go.  If it takes me a few months to do this, is there anything I need to do with the rest of the car to keep it from deteriorating?  Can the engine be started to idle while the transmission is out, to keep things flowing?  Are the brakes and cylinders I just put in (new) going to leak and have problems from non-use? 

 

I wouldn't worry about your car laying down while you work on the transmission.

 

I assume the floorboards come out of your car and that greatly reduces the aggravation of pulling the tranny. Most of the work can be done inside the car instead of below it. Work methodically and you'll have the clutch exposed in no time. These are very simple cars. Best wishes!  ?

[ChrisMinelli]

16 minutes ago, Sam Buchanan said:

 

 

I assume the floorboards come out of your car and that greatly reduces the aggravation of pulling the tranny.

 

Haha, funny you should mention that.  Some bonehead glued the carpet down in the car.  Which I didn’t discover until I needed to access the master cylinder for the first time.  That was fun. 

[JerseyHarold]

The only floor panel that comes out in a '52 Plymouth is the one around the pedals.  Everything else is (or, was) solid.

 

Also FWIW, '52's came with an Auburn clutch and a different return-spring setup than the '51's.

[Tooljunkie]

Sounds like you need everything. 
saying that, you need to determine the cause of the failure to prevent it happening again. Loss of free play in pedal would be whatbi suspect. So throwout bearing was putting slight pressure on clutch fingers and allowing disc to slip 

as it heated up it warped.so when you press pedal the warpage causes drag making it impossible to get into gear. I hope this makes sense. 
 

Above advice is right on the money, clutch, pressure plate, pilot and release bearings. Gaskets if needed,and deal with the countershaft potential leak. 
flywheel will also need machining.

if it has hot spots it will likely need to be ground instead of cutting. 
 

do it once, do it right, good luck with your endeavour!