Sealing Leaks at Axle Tube Casting

[GrigioTR]

After removing all rear brake parts and backing plates to find the cause of transmission oil dripping down the rear shock mount arms, it appears the leaks are coming from the where the axle tubes insert into the castings on the end of the tubes. Probably not a common problem. I am guessing when all parts of the rear axle were chrome plated, acid dipping may have been the culprit.

In addition, the car has an Empi camber compensator with custom end mounts that attach the leaf spring to the casting, not the tube. Over time this would/could cause the casting to flex on the axle tube and allowed trans oil to weep. At least these are my assumptions.

To potentially get more than surface coverage at the casting/tube mating point, I am thinking about using Permatex spray sealant vs Permatex RTV sealant.

I am hoping someone on the Forum has experience with the spray on sealant and will give me their impression on the product. I have no idea if the spray- on will hold up if the cause of the leaks is in fact minute flexing of the casting at the tube.

Thanks in advance for any input and advise.
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1956 VW w/ blow through turbo
1984 Porsche Carrera

[61SNRF]

I would think Green Loctite sleeve retainer is worth a consideration.
As long as Mfr's recommended prep of the metals is followed it will fill any gaps and should seal against any fluids.
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-Bruce

An ounce of prevention is worth a pound of cure.

[scrivyscriv]

The sleeve retainer would be a good idea if you could get the two parts separated to apply it.. it does not tend to wick down into crevices, in my experience.

Honestly there really isn't a great solution that I can think of.. it's chromed, so tig welding is out of the question. It's already assembled, so sleeve retainer isn't a good fit. And you can't get to the inner joint surface by its design, so RTV isn't looking good either. I think about the best you could do would be a thin smear of RTV at the leaking joint after thoroughly cleaning with isopropyl alcohol or similar... ultimately you may want a higher quality tube. Aftermarket chromed parts, as I have heard, tend to have a poor reputation for quality and fit.

As to the cause of the leak... I would expect it to be from a loose or improperly machined fit between the two pieces; not necessarily any flexing.
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Robert in Memphis
Dünkelgrügen 1967 Java Green bug thread
Engine rebuild thread
If you're ever in the Memphis area, you are welcome to stop by for advice and help.

[GrigioTR]

Thanks to all of your suggestions.

I should have mentioned in my post that all of the parts are original equipment, and the chroming was done by the previous owner. The transmission and tubes are 1964 VW. It is for this reason I posted in the 1958-1967 sub-forum.
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1956 VW w/ blow through turbo
1984 Porsche Carrera

[61SNRF]

I don't know what you mean by spray sealant, never used, seen or heard of it. What was your plan?

I still believe green Loctite would fit the bill. Not only will it seal the fittings but would also strengthen the whole assembly and resist shock loads.

You would have to R&I the tubes and press them apart, then on going back together is when you would apply the Loctite to both parts.
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-Bruce

An ounce of prevention is worth a pound of cure.

[GrigioTR]

I am going to use 2 Permatex products in my attempt to seal my transmission oil leaks coming from the rear axle bearing casting/axle tube.

First up will be a Permatex gasket sealer (meant for oil environments). I will clean the joint with multiple liberal doses of brake cleaner. Then apply a thin coating around the casting/tube joint. Pushing it into the seam with my finger. Once dry, 5 spray coatings of Permatex spray sealant.

Fingers crossed!
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1956 VW w/ blow through turbo
1984 Porsche Carrera

[scrivyscriv]

[esde]

You can remove the tube from the end casting, though it requires access to a press. There is a tapered lock pin to drive out, and then set everything up with the right size socket or seal driver and it comes apart pretty easily. Use some sealer when reassembling. Going back together you need to be careful that the lock pin slot is aligned with the hole in the casting, and that the boot and retainer have been installed.
Here's a random pic from the gallery.

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modok wrote:
Bent cranks are silent but gather no moss. I mean, ah, something like that.