Rear Axle Seal/ Rear Axle Problems

[Subzero]

I've struggled with fixing my leaky rear axle seal since I've bought the truck, the seal has been replaced 4 times and the bearing twice. Each time it holds for a couple weeks then begins to leak. Right now I just keep adding rear axle fluid and let it ride, as I have no money to throw at it and don't know what I should do, but that's the point of this posting . There is no ridge or anything like that on my axle but it still leaks. I am wondering if I should replace the entire rear end or just the singular left axle with a new seal and bearing. What years would fit my truck as a direct parts swap for the single axle or the entire rear end? What would you recommend trying so it's the most cost effective, yet will fix the problem. ive found a few ads on Craigslist for f100 rear axles but I'm not sure they'll fit or how to measure them.Thanks

[sargentrs]

Are you sure you're axle vent is open and functional? Are you over filling? Were you extremely careful when sliding the axle in, through the seal, to make sure that you didn't rake it across the bottom rubber of the seal? How about the other seals when you changed them? Did you see anything on them that might indicate why they're failing? Short of a bent or scarred axle, or excessive play in the differential or axle bearing, it should not be leaking badly.

[Subzero]

Thought of the vent too, it was replaced a long time ago right after it leaked the first time. It's also never been overfilled. The axle shouldn't of cut the seal, I was careful and took time to ensure it was done right. My buddy who ownes a shop did it the last time though, he knows these trucks well and I'm sure also did it properly. I haven't touched the drivers side seal as it's not leaking at all, I'd rather let it be and not risk it never sealing up again like the passenger side one. Doesn't seem to be scarred but it could be slightly bent or something along those lines, it's really got me stumped.

[sargentrs]

Can you tell if it's leaking where the rubber meets the axle or around the outer metal edge of the seal where it meets the axle housing?

[Subzero]

Not really sure to be honest. It just leaks out and gets all over the brake drum. If it is leaking in between the metal part and not the rubber seal that meets the axle, how would you fix that?

[ultraranger]

Smear a thin layer of Permatex Ultra Black on the outer edge of the seal's metal housing, before you install the axle seal into the bore on the end of the axle housing tube.

http://www.autobarn.net/per82180.html?s ... Mgod02AAkw

[tnlprt]

Are you sure the axle is not bent

[Subzero]

I'm fairly positive my friend did use the permatex on the seal when he did it. I don't know if the axle is bent or not, it could be though. If it is bent it is not obvious and is very slight. How do you check?

[sargentrs]

Not really sure to be honest. It just leaks out and gets all over the brake drum. If it is leaking in between the metal part and not the rubber seal that meets the axle, how would you fix that?

I think that would imply it's at the rubber seal then. I'm leaning toward the bent axle scenario. Check the axle shaft with a long straight edge, like a level, and then check the axle flange to make sure it's perpendicular to the shaft, with a square or protractor. Or just pull it and take it to a machine shop and have them check it in a lathe.

[ultraranger]

Put a dial indicator on the wheel flange's edge and then on the wheel mounting surface of the axle flange. Turn the axle with the dial indicator at each location. If there's more than .005" of deflection on the needle, your axle has problems.