77 rear axle with 31 spline shaft, which bearing???

[latrucker]

I am replacing my rear axle bearing and seals but can't figure out which bearings i need. I have a 77 rear axle with disc brake conversion that has 31 spline Dutchman axles. Can anyone tell me which bearings and seals I need so I can source the parts before I tear it down. I would like to go with a sealed bearing, let me know if this would be better or worse than staying with the tapered bearing and race setup.

 

[Shimmy]

since you have aftermarket shafts maybe you have set20? probably best to pull them and check. post a pic?

 

[Apogee]

If you currently run the SET20 tapered roller bearing, then the ID of the bearing will nominally be Ø1.5625". While there are aftermarket sealed ball-type bearings that match the ID, they may require a spacer to maintain the same axle offset when installed in place of a SET20 setup...Dutchman requires you to specify the bearing so that they can machine the shoulder accordingly if I'm not mistaken, so they would be as good a place as any to ask that question.

Additionally, while most of the aftermarket ball bearings with the Ø1.563" ID have o-rings in the outer race along with oil/grease-rated inner seals, they technically don't require you to run inner axle seals pressed into the housing ends, but I would still suggest running them.

You mentioned replacing the external oil seals on the SET20's, so are you having issues with the SET20 bearings leaking or is there some other reason you're thinking about converting back to ball-bearings? Another potential solution is to run inner oil seals with the SET20's and then just pack the SET20's with wheel bearing grease. A lot of my customers do that to avoid some of the leaking issues commonly attributed to the SET20 bearing/seal combination, especially with aftermarket brakes and retainer solutions.

Tobin

 

[Madgyver]

set20

 

[WPS 73 Bronco]

 

[DirtDonk]

Thanks, WPS. But that seal won’t work in the OP’s housing.
He’s got a ‘77, which is automatically a big bearing.
And presumably a set 20, which is also a “big” bearing, by size at least.

And looking up the seals on our site, looks like I have a correction to make to the page.
Description lists them up to 77 for small bearing. But as far as I know, 76 and 77 never came with a small bearing.

 

[DirtDonk]

I am replacing my rear axle bearing and seals but can't figure out which bearings i need.

Why are you replacing them? Issues with the bearing, or perhaps some oil leakage?
And do you know for a fact that you have separate inner seals? Did you build it?
As mentioned, Dutchman axles would theoretically have Set-20 bearings and no inner seal. Unless the installer utilized them.

I have a 77 rear axle with disc brake conversion that has 31 spline Dutchman axles. Can anyone tell me which bearings and seals I need so I can source the parts before I tear it down.

Did you buy it this way, or did you build it yourself? Which disc brake kit is being used?

I would like to go with a sealed bearing, let me know if this would be better or worse than staying with the tapered bearing and race setup.

As said, you don’t have a choice. Sealed bearings are nice and simple, but if your axles were made for Set-20 tapered bearings, then that’s what you have to use.
If made for standard sealed ball bearings, then that’s what you use. With inner seals…

 

[latrucker]

If you currently run the SET20 tapered roller bearing, then the ID of the bearing will nominally be Ø1.5625". While there are aftermarket sealed ball-type bearings that match the ID, they may require a spacer to maintain the same axle offset when installed in place of a SET20 setup...Dutchman requires you to specify the bearing so that they can machine the shoulder accordingly if I'm not mistaken, so they would be as good a place as any to ask that question.

Additionally, while most of the aftermarket ball bearings with the Ø1.563" ID have o-rings in the outer race along with oil/grease-rated inner seals, they technically don't require you to run inner axle seals pressed into the housing ends, but I would still suggest running them.

You mentioned replacing the external oil seals on the SET20's, so are you having issues with the SET20 bearings leaking or is there some other reason you're thinking about converting back to ball-bearings? Another potential solution is to run inner oil seals with the SET20's and then just pack the SET20's with wheel bearing grease. A lot of my customers do that to avoid some of the leaking issues commonly attributed to the SET20 bearing/seal combination, especially with aftermarket brakes and retainer solutions.

Tobin

I recently pulled the driver side axle out to replace the wheel studs and the rubber coating on the seal that slide over the bearing was hard and torn. Figured I would replace just to be safe. Bearing’s actually look good but I’m sure the bearing will get damaged when removing to replace the seal. Please correct me if I’m over thinking this. Seal wasn’t leaking before I pulled the axle but figured it would start leaking once I start driving it again.

 

[DirtDonk]

I don’t think you’re overthinking it. I think it would leak for sure if it looks compromised now.
Even perfectly good ones leak if the seal surface is not pristine.
Too bad it got damaged when you were removing it. There’s always another layer of pain and hassle beneath the current one!

Did you find an inner seal in the axle housing?

 

[latrucker]

I don’t think you’re overthinking it. I think it would leak for sure if it looks compromised now.
Even perfectly good ones leak if the seal surface is not pristine.
Too bad it got damaged when you were removing it. There’s always another layer of pain and hassle beneath the current one!

Did you find an inner seal in the axle housing?

I haven’t taken it down yet. I wanted to source all the parts before I started to replace the bearings. I don’t think it does by the way you can move the axle up and down when trying to stab it into the 3rd member.

 

[Apogee]

Replacing the external oil seals on the SET20 bearing assemblies is one of the reasons I don't prefer them, as you need to remove the bearing from the axle to do it. While you can buy the retainer collars separately (and pretty inexpensively), it does require a press to get the bearing off intact and even then there's always a risk of damaging it in the process depending on the press tools you use to get it off. The collar should be cut and chiseled, otherwise it can and will damage the axle shaft if pressed off due to the relatively larger interference fit between it and the axle. IMHO, your best bet would be to just purchase a new SET20 bearing/seal and plan on replacing it while keeping everything as-is...why reinvent the wheel if you don't need to unless I'm missing something?