VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 Torque Tube Leak

This might be an inherent design flaw, but how does one stop that annoying leak from the compression nut on the torque tube U-joint housing slip-joint ? I've had several mid-30's Chevy's in the last 30 years (present one is a '37 coupe), but I've never been totally successful in elliminating this leak. I have it down to only a small drop every once in a while (a drop every couple of days when parked), but I HATE -Bob

Bowtie Bob, don't consider the dripping of oil or grease from an old Chevy as something bad! just think of it as an indicator.....as long as it is dripping it has some grease in it, the time to worry is when it STOPS dripping! Ha!
I know what you mean!

Hey Bow Tie Bob, I'm in the same camp. Are you referring to the "Propeller Shaft Bushing / Oil Seal"? (If you have a Filling Station catalog, it's their part number V-101) I was counting on having to replace this on my '37 1/2 ton when I start to build the chassis back up. If there's something else I need to attend to, the time is drawing near!

If you find the answer, let me know. :confused:

Filling Station part V101 is the bushing ( to support the inner drive shaft)and seal. This seal prevents the gear oil in the transmission from running down the inside of the torque tube and overfilling the differential.The seal necessary to stop external leaks is part of U joint gasket set #FS-125.It would be the last seal in the picture on top of page 165.The seal is a heavy felt and one side was rubberized (on the original GM version at least).The seal is compressed by tightening the very rear collar.If it continues to leak I would check the outter surface of the torque tube to be certain that its smooth.Also I believe that the felt seal has a large washer on each side to help compress it.Are the washers missing?It was always more common to have a leak at the ball rather than the rear seal.

Sorry - should have been more specific. The leak is external, at the large compression nut or collar on the rear end side of the U-joint ball (Chevy group #5.564 - sorry, but I'm the only VCCA member without a filling Station catalog - I'll have to remedy that, too!!). In the torque tube ball seal kit I purchased recently, the seal or "packing", as Chevy refers to it (Chevy group #5.580), is made of rubber or neoprene, instead of the original felt that Gene refers to. Both original large metal washers are in place (one on either side of the packing)and I used a chain wrench to tighten the nut / collar a bit more than hand tight. The u-joint ball is NOS and I cleaned it good with fine emery paper to make sure there weren't any burrs or scratches at the pivot end and there are no leaks at the front, only at the rear of the u-joint ball. I polished the packing contact surface area of the propeller shaft, as it has to slide in the packing. The leak is much less than I ever had on one before, but there's still a drop or two every few days. Maybe these all leak a bit and I'm expecting too much for a 65 year old design - whadda ya think ?? :confused: :confused: :confused:


-Bob

Bob I think either when the propeller shaft and U joint run out of grease or if gravity quits you will quit having a drip, and even after gravity quits there will be that final drop that won't fall till you are under the car and looking up at the spot!.....just get one of those cookie sheets to catch the drips, I use a 3' wide and 20' piece of clear plastic under all of my old Chevys, you will be surprised how many strange puddles that I find after being gone for a couple of weeks.

Bob,I knew where your leak was but was answering Chevrolets question in the first part of my reply..sorry..I should have been more specific...You just answered your own question .If the seal in the kit is a heavy material as you say it will take quite a bit of force to squeeze it so it seals on the outter part of the torque tube.Just give it another "tug" to compress it more and it should stop leaking.This was not the usual area to leak-even my Power Glide is dry in that area.(modern materials are not always best on old Chevrolets)

We have used o-ring on that area on earlier Chevys. It has stopped all the leaks from that area. Keep the two metal retainers in place and find an o-ring that will fit the space. I agree with Gene that the ball is the area that typically leaks.

I thought I would add this "positive" side to the leaking torque tube, I use really quality grease in my trannys and differentials, my thinking is that as it leaks going down the hiway the grease is coating the fragile ferrous parts and keeping them from rusting!

The original felt seal was about 1/2" thick (in cross section ) and 2 1/2" in diameter.....If the modern less conforming seal insists on seeping I would-Loosen collar and slide back.Slide back the first metal washer and clean out all traces of gear oil (with brake cleaner).Then would fill cavity with a 1/4" layer of ATV Silicone sealant.Lightly tighten collar and allow RTV to cure.Then a day later retighten the collar as necessary.The RTV will remain flexible and prevent it from leaking...This is a slip joint and there is some sliding movement....The pre 1934 had only a ring of cork inserted into the end of the ball housing-and it was non-adjustable-Yes,an O ring would be a big improvement on those years.....I used this RTV proceedure on one of my knee-action units 15 years ago and its still dry.

To paraphrase "Mystery Science Theater 3000":

"Well lookit that! it say's right here in the catalog (The filling station):

A leaky U-joint housing is the most common problem with the closed drive line vehicles. This seal set replaces all the seals required to keep gear oil inside were it is needed. (NOTE: early models without a screw-on flange at rear of ball housing will require a FS-4356 "O" ring seal.)

I hate it when I miss things that are written down like that! Thanks Chev Nut.

There's similar text for V-101 "Drive Shaft Bushing & Seal"...

Is a "Dry transmission" the only way you will know that a new Bushing and Seal is needed? Seems like a lot of damage can be done before one realizes their transmission is dry, expecially in a non-syncro trans.

If the bushing and seal are needed the leak would be internal.If this is the problem the gear oil in the rear end will be "overfilling"-and when you remove the filler plug you will know in a hurry

I can imagine! So I guess the real answer to my question is that you need to check the lube level in the differential every "so-often", not "never in the lifetime" which has been my experience so far.

I can see by the extensive wear on the suspension components of both of my trucks that the lubrication schedule has to be be followed, but probably hasn't been in either case.

Thanks for all the input, gents! I'll try some of your suggestions and experiment some more. I'm on a quest!!!! :rolleyes: :rolleyes: :rolleyes:

-Bob

I also have had great success using a modern 'O' ring instead of the original felt packing. Go to your local Caterpillar dealer or oil seal/bearing supplier to find one the right size. Put the O ring between the original metal rings, apply plenty of grease and presto, no more leaks !!!

Also about the "O" ring application a trick I learned in the oil patch, when the parts can be seperated but not parted completely, cut the "O" ring at an angle with a sharp knife then a dab of superglue to the ends and stick it together around the torque tube without taking the compression nut completely off of the torque tube,or parting the u-joint .

Thanks for the input, guys. So far, the leak seems to be resolved, but I'm keeping an eye on it.

-Bob