Set 20 Bearing Seal Question

[Shimmy]

1977 here and i'm in the middle of installing my new 3rd member with 31 spline axles from TBP. These axles use 20 set bearings. Do i understand this correclty, I'll need to remove the axle seal that is currently in the rear axle and the these new shafts slide in without that inner seal? this is because the set 20 bearings have an outer seal and use the diff fluid for lube? I also noticed my driver side housing seems mangled a bit. wondering if this will cause seal issues. Should i use silicone or an RTV or sorts?

Sorry, this just feels so dumb asking... lol!

 

[toddz69]

Correct. Remove that seal. I'm a big fan of sealing leaky axle housings with hylomar. It doesn't set up so it makes disassembly a lot easier. Great tip from @ntsqd years ago when my brand new Currie housing leaked.

Todd Z.

 

[Shimmy]

Correct. Remove that seal. I'm a big fan of sealing leaky axle housings with hylomar. It doesn't set up so it makes disassembly a lot easier. Great tip from @ntsqd years ago when my brand new Currie housing leaked.

Todd Z.

which hylomar do you use?

 

[ntsqd]

I try to buy the real stuff, like this: https://www.grainger.com/product/HYLOMAR-Gasket-Sealant-Hylomar-M-13P427

If you've never used it before I strongly suggest wearing clothes that you don't care about. If you get some in your clothes it isn't coming out. Lacquer Thinner will slowly dissolve it, but nothing else that I've tried even touches it.

 

[broncojohn]

@ntsqd interesting stuff so are you putting it on the outside of the seal or the OD of the bearing surface

 

[phred]

I usually add a small thin bead of anaerobic sealer along the oring seal on set20 bearings. I’ll have to try to Hylomar in the future.

 

[ntsqd]

Given that I detest semi-floating axles I try not to have anything to do with them. But, when there's a gasket I smear some hylomar on both sides of the gasket. When there's a o-ring I use the Hylomar on the o-ring itself and in it's groove - i.e. deploy it like it is an assembly lubricant. When it is two flat metal surfaces I smear it on one of them before assembly. I very much prefer to use Hylomar on full-float axle flanges instead of silicone. I usually do not use any sealer on a rubber lip seal. If I do, I tend to use The Right Stuff silicone (THE best silicone that I've ever used - and now the only silicone that I do use).

That is the advantage of Hylomar over something like The Right Stuff, you can easily disassemble the joint. And sometimes you can reassemble the joint without needing more (say in the field or on the trail). It may or may not weep a little when re-used like that.

 

[Apogee]

The "skirt" on the oil seal for the SET20 bearings pushes out into the the bore of the housing end, much like a bellows, when the seal is compressed. If you have any axial scoring, corrosion, etc, in the housing ends, I would strongly recommend using a sealant on the bore and/or skirt of the seal. And as Todd pointed out, even new housings can leak for what appears to be no reason. I tend to avoid the SET20's for this reason and stick with the traditional sealed ball bearings, but otherwise RTV, The Right Stuff or Hylomar are all serviceable options to keep the oil where it belongs.

I do have some customers who run the inner oil seals and then pack the tapered roller bearings with grease due to issues with leaks, treating them much like you would a front wheel bearing. This is similar to what some of the 3/4 and 1-ton axle crowd have done to prevent their rear hubs from leaking oil onto their brakes.

 

[gr8scott]

1977 here and i'm in the middle of installing my new 3rd member with 31 spline axles from TBP. These axles use 20 set bearings. Do i understand this correclty, I'll need to remove the axle seal that is currently in the rear axle and the these new shafts slide in without that inner seal? this is because the set 20 bearings have an outer seal and use the diff fluid for lube? I also noticed my driver side housing seems mangled a bit. wondering if this will cause seal issues. Should i use silicone or an RTV or sorts?

Sorry, this just feels so dumb asking... lol!

Yes, remove that seal and tap in the race of the SET20 bearing.

 

[toddz69]

which hylomar do you use?

Here's what I use. Has "Racing" in the title so it must be good . I used to be able to get it at the corner auto parts store - when Permatex had it under its banner. I order it online now. Looks like I need to get some more!

Todd Z.

 

[Shimmy]

Here's what I use. Has "Racing" in the title so it must be good . I used to be able to get it at the corner auto parts store - when Permatex had it under its banner. I order it online now. Looks like I need to get some more!

Todd Z.

looms like this is now called hylomar M. drove to 4 different places today and came up empty. placed my order online