9 inch bearing issues

[Broncopower96]

A mechanic and I rebuilt the 9 inch rear end this afternoon. Installed a true trac and 4.56 gears. When we attempted to press on the new axle bearings, they would not budge. The axles are new 31 spline Yukon axles and the bearings are timken 514003's. We used a press with a lot of pressure (see the flexing in the picture). When that didn't work, we put the axles in the freezer. Still no luck, with either axle! We also compared the bearings to a bearing my mechanic had at the shop, and they were a match. The mechanic thinks that the axles are off, because usually the bearings press on no problem. Has anyone here experienced similar issues, specifically with Yukon 31 spline axles? I may have to see about returning the axles if I can.

 

[dave67fd]

I would first confirm OD of the axle and ID of the bearing and if in spec then I would try to heat the bearing before freezing the axle. Sometimes they slip on without a press.

 

[NC-Fordguy]

Are the rectangular rods hollow?

I've never pressed on bearings like in your picture. I always use arbor plates and a bearing splitter. Sometimes it can take 10 or 12 tons of pressure to get a bearing to go on.

To answer your question, yea I've run into an axle shaft being out of spec, but did get the bearing pressed on. The axle shaft sat on the work bench for and hour or so and the bearing simply fractured all by itself. It was one of those wtf moments.

I'd mike the axle shaft and the inside of the bearing to see if there is an issue between the two.

 

[Viperwolf1]

Aftermarket axles usually use a bearing that has a slightly larger ID. Stock bearings won't fit. The stock bearing was a sealed/permanently lubed bearing and needed a separate seal in the axle housing to keep the oil in the housing. The aftermarket bearings are not sealed and require oil from the housing for lube. A separate seal needs to go on the axle shaft before the bearing to keep the oil from leaking out.

 

[Timmy390]

I thought ALL aftermarket 31 spline axles took set 20 tapered roller bearings as the OD of the shafts are bigger than the original 28's.

Got my 31's from WH and they came with Set 20's already installed.

Tim

 

[Broncopower96]

Timmy390 - that's right, the 31 spline axles take the set 20's! I looked through my parts stash, and I have the set 20's as well. Looks like I didn't cause any damage trying to press the smaller bearings, which is good. I'll go ahead and press the set 20's and call it a day. Thanks so much!

 

[Digger556]

If your axles are:

1.561"-1.565" OD, you need Set 20 bearings

1.531"-1.535" OD, you need the 514003

 

[Broncopower96]

Good information to know. I just measured the axle shaft at the end where the bearing seats. Using a micrometer, the axle is approximately 40 mm in diameter, or 1.57". Set 20 for sure. Thanks for the tip.

 

[DirtDonk]

I believe we still sell both. The Extreme axles are Set-20's and the Heavy Duty versions are standard large or small sealed bearing.

I don't know if Yukon sells both styles too, but I have seen other people comment in the past on Yukons they'd bought not being sized for the standard bearing.

Paul

 

[Broncopower96]

I knocked out the old axle seals. Just to make sure, I don't press in a replacement seal do I? I think I should just install the larger set 20 seal that goes on the axle along with the bearing. I've attached pictures of both. Thanks for the help!

 

[Broncopower96]

Here's the new set 20 seal.

 

[bronconut73]

My WH rear 31 spline big bearing axles used a Set 20 bearing that has an o-ring on its outer surface that sealed against the axle. I do not believe I had any other seals.
Axle, retaining plate, bearing with o-ring on it, spacer.

 

[Broncopower96]

I believe it goes axle, retaining plate, seal, bearing, and then retainer ring/spacer. I believe the o ring you are talking about is used to snug up against the seal like so:

 

[Broncopower96]

Here's a pic with the two together. So if this is in fact correct, do I still need to press in the stock style seal into the axle tube? It looks like there would be room for it, but I doubt I need 2 seals.

 

[migs]

That is the correct order and No inner seal in the housing, You want the oil to be able to get to those bearings for lubrication.

 

[Broncopower96]

Thanks. Also, the set 20 bearing appears to be packed with grease. If that is the case, then does it still need gear oil for lubrication?

 

[Viperwolf1]

Thanks. Also, the set 20 bearing appears to be packed with grease. If that is the case, then does it still need gear oil for lubrication?

It still needs oil. Grease is probably there to give it some minimal degree of lubrication until oil gets sloshed to the housing ends.

 

[chuzie]

I am running the yukon 31sp in my 75 rear. Have a sealed roller on the driver side. Ever since I replaced my passenger side because of a defect, it has has a set 20. I HATE IT because I am using explorer brakes and getting all that mess to fit together is a nightmare, especially the seal.

Not sure how I have a sealed roller on the driver side unless I somehow squeezed a stocker on there somehow.

Is there no PROPER alternative to a set20 on these yukons? I would LOVE to go back to a sealed roller.

 

[chuzie]

Talked to Randy's and they gave me a part number for a sealed ball to fit on the Yukon 31 spline large bearing, BCA88128RB. It is pricey at $68 but if it means I can be rid of this damn set 20, it will be worth it.