VCCA Home Forums TECHNICAL - 1945 AND NEWER 1949-1954 Leak in torque tube seal

I installed a replacement torque tube/crown gear and pinion. As part of the swap I installed an Oakie bushing and all new gaskets and seals. The flex at the ball was checked before final installation.
Unfortunately I have a significant leak at the sliding joint on the torque tube. I have tighten the joint as tight as I am comfortable doing. I am not looking forward to dismantling the entire U-joint, ball assembly etc to change the seal at the sliding joint.

Any suggestions, advice for this backyard mechanic?
Dave B

That slip joint is a packing type seal. There should be steel washers on each side of the packing to make sure it compresses properly when you tighten the knurled nut. If those washers were not installed I doubt if it will seal. When you squeeze the packing it gets tight on the outside of the slip tube.

Use a strap wrench to tighten the knurled cap/nut. It does need to be fairly tight. If you try to tighten it with a pipe wrench or large adjustable pliers it will seem like it is tight even though it is not. The pressure from the wrench jaws or pliers will distort the nut. The threads will get so tight underneath the jaws that it prevent you turning the nut to compress the packing.

Thanks Rusty for your input and advice. I’ll give a strap tightener a try. I plan to get the car up on jack stands in the next few days and see what’s up.
I did notice the seal, which came from Chev’s of the 40’s, was much narrower than the previous unit had, the new one was maybe 3/8 whereas the previous was more like 1/2 to 9/16. Not sure if it is an issue but more of an observation.
Laying on the garage floor ain’t as easy as it used to be!
Dave

Hi Dave,

Your observation about part differences is what all of us are seeing in this world of replacement/reproduction parts. What is so frustrating is that sometimes they work and sometimes they don't.

A key point is having the 2 steel washers in that stack. They need to be there to apply load to crush the seal so the it expands inward and seals against the OD of the bell tube.

That is the basic concept of any packing type seal. The packing material is constrained such that when the load is applied it can only distort in one direction.

Make sure that the OD of the bell tube is smooth and clean. There has been more than one person who thought they were doing the right thing by painting the whole length of the bell tube. That seal needs to be on bare, smooth metal.

I polish that portion with #400 sandpaper. Let the axle hang down as far as it can. That exposes the maximum amount of bell tube. If you want to get a little closer loosen the nut and slide it with the packing forward. Then you can polish right next to the front end of the axle tube. Wipe it clean and put a light coat of oil on it before you reassemble.

Thanks Rusty for your reply. The car is up on jackstands and I removed the access panel from the transmission hump, I’m planning to use 85/140 gear oil as suggested by Gene and it’s easier to use gravity rather than my cheap fluid pump.

I did install the seal with the steel rings so I understand what you are describing as the crush creates the seal contact with the torque tube.

I am going to do as you describe to polish the torque tube as during the install we did rough sand that area and it probably needs to be cleaned up with fine sandpaper. Good suggestion!

Tomorrow’s another day and it’s supposed to rain so good time to be in the garage.

Stay well and thanks for your help.
Dave

You are making good progress! Yes, smoother is better for that seal to work. Even with s strap wrench it has to be tighter than you might think.

Hello Rusty
I cleaned up the exterior of the torque tube with 400 grit paper and did a test run only to find some dripping gear oil. I got aggressive with tightening the seal ring and put an exhaust pipe clamp on to keep the seal ring from loosening, seems to be working as leakage is minimal.

Thanks for your help and the to the author of the clamp suggestion (whose name I can’t remember) for getting my car back in action.

Stay well!
Dave B