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Leaking rear wheel bearing

Tucknkitty

Newbie
Joined
Nov 9, 2013
Messages
48
Guys,

I’ve been having issues with my passenger side rear wheel bearing on my 77. I have 31 spline axles and use set20 bearings and after a few thousand miles the same side always starts to leak. I’m starting to think the passenger side housing/end is the culprit as I had a bear of a time getting the race out last time. It’s a slow leak now but I know it’s going to have to be replaced.

I have arbs on it too and I do deal with a little diff oil from the compressor- which is sadly common with the arb set up. Do you think it’s a pressure issue? Or a end issue? I have some rear end work I need to do - replace the shackles and maybe add a stiffer torision bar to help prevent axle roll, that 408 is stout...

Any one dealt with this before? Any tips?

TnK
 

Apogee

Contributor
Bronco Guru
Joined
Nov 26, 2005
Messages
6,033
In general, I avoid the SET20 bearings when I can due to their tendency to leak, especially in used or worn housing ends. With that said, if you don't have enough preload on the seal, the outer skirt portion of the seal doesn't bulge out as much as it should and doesn't seal as well as it should/could.

Some people add a thin bead of RTV to help with any issues due to scoring in the housing ends, corrosion, pitting, lack of preload, etc. Alternatively, you can fill any score lines, pitting, etc with super glue or something similar (JB Weld) and then sand it smooth to achieve a smooth sealing surface. Last but not least, you could swap over to a sealed ball bearing with a 1.5625 ID and call it a day, but you might need a spacer to maintain the proper axle offset...I don't remember how much they differ in terms of installed width.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,355
I'd try the silicone solution for sure. At least it's worth a first shot, as it's cheap and easy.
Certainly if you see nicks and scratches though, smooth them the best you can.

But have you checked your vent yet? Even if the ARB is leaking pressure the vent should be more than capable enough of evacuating it. By the time it can't, you have a major leak and the ARB function would likely be compromised anyway.
If your vent is fully clean, then definitely add some sealant to see if that helps.
In my opinion, that stop-gap measure beats the heck out of buying another Set-20 and installing it!

When new (remember this was a factory Ford part) they did not have a tendency to leak that I ever heard about. I think they figured that by the time they did start to leak (usually at over 100k miles I thought) it was a good time to replace the wheel bearings anyway.
But having them start leaking as quickly as you're seeing, you need to try a couple of different Plan-B's I would say.

Good luck!

Paul
 
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