New front axle unit bearings coming apart

[bjoneill]

I needed to replace the ball joints on my '03 TJ Rubicon. Ended up down the rabbit hole. The axle nuts WOULD NOT come loose, even with heat, 3ft breaker bar extension, bent 1" angle iron and broken wheel stud, so decided to replace the axle shafts right and left.
I ordered the Alloy USA replacement kit, which included new unit bearings.
When I installed the kit the axles protruded just enough through the hubs to get the cotter pin in, but not with the nut retainer, even torquing past 175.
Everything seemed tight, if not the way its supposed to be.
But after only 20 miles or so I pulled the front wheels to check everything and found both wheels loose. Took the wheels off and found the axle/unit bearing moves inboard/outboard at least 1/4". After taking it apart the unit bearings were loose, actually they appear to be coming apart.
I was able to press them back together and they are tight, but when reinstalling, the axles still don't extend out. The unit bearings are tight and solid against the axles.
All the parts came in one box as a kit from Alloy USA..
What holds the bearing unit on the inboard side, the oil slinger pressed against the axle?
2nd question, which direction do the outer axle slingers go? Each axle had it differently when I took it apart. Seems the wider flange should go against the bearing seal, but the online pics show it against the axle. The Jeep has, obviously, been apart before.
Simple ball joint and tie rod end job?!
Thanks in advance for your help.

 

[CharlesHS]

Since you have a Rubicon you have the Dana 44 front differential.
Are you sure that you were sent the proper unit hub bearings ? They may be for a different application and have the wrong offset.
Compare all the unit hub bearing dimensions that you removed to the one that was sent to you.
The bearing is held into the unit flange by the axle nut torque.
There should be a large washer that goes under the nut against the bearing then the keeper ring that fits over the nut and then the cotter pin.

 

[bjoneill]

It was sent as a kit, axles, u-joints, and unit bearing hubs.
I'll recheck, thanks

 

[AndyG]

Keep us posted .

 

[bjoneill]

Here are some pics.
the bearing unit won’t seat all the way. Something inside is binding. I’ve tried pushing, tightening the nut and hammering. This is as far as it goes.
I don’t believe or see that it could be “keyed” some way to allow only one insertion.
Ideas?
I’m going to call Q-tec this morning. Alloy USA has been no help

 

[Lou]

The stub shaft should fully engage the unit bearing. Can you take a pic of the stub shaft splines removed from the unit bearing?

 

[Jerry Bransford]

The uni

Since you have a Rubicon you have the Dana 44 front differential.
Are you sure that you were sent the proper unit hub bearings ? They may be for a different application and have the wrong offset.
Compare all the unit hub bearing dimensions that you removed to the one that was sent to you.
The bearing is held into the unit flange by the axle nut torque.
There should be a large washer that goes under the nut against the bearing then the keeper ring that fits over the nut and then the cotter pin.

The unit bearing hubs and stub shafts are the same for the TJ's Dana 30 and Dana 44 front axles. The front Dana 44 is pure Dana 30 from the axle tubes outward. Only the diff, its housing, and the inner shaft is Dana 44.

 

[mrblaine]

Here are some pics.
the bearing unit won’t seat all the way. Something inside is binding. I’ve tried pushing, tightening the nut and hammering. This is as far as it goes.
I don’t believe or see that it could be “keyed” some way to allow only one insertion.
Ideas?
I’m going to call Q-tec this morning. Alloy USA has been no help

View attachment 213864

View attachment 213865

We see this often. You have an extreme case of tolerance stacking. Typically the issue is the splines on the stub shaft are short of going far enough towards the flange on the stub and the splines inside the unit bearing are not cut deep enough away from the inboard side. Over time, the UB loosens up slightly due to the splines working in deeper.

You are the victim of an extreme case of one or both.

The stub shaft is actually a big bolt that holds the unit bearing together once installed. If that doesn't happen, then you get what you are experiencing which is separation of the two halves that are pressed together until they get bolted by the stub.

This is not a Q-tec issue, this is 100% an Alloy USA problem and they need to handle it. The unit bearings are likely trash since they have been driven on while separated. I personally would not trust them after that.

 

[mrblaine]

Also, what is the piece with the arrow? Is that a sheet metal slinger they put on the stub shaft before you stuck it in the unit bearing or is it part of the UB that is separated?

 

[sierradmax]

Perhaps you were sent the wrong shafts. I've never seen a set if shafts with what appears nuts to hold the u-joint caps on...

 

[Lou]

Perhaps you were sent the wrong shafts. I've never seen a set if shafts with what appears nuts to hold the u-joint caps on...

Those are grease zerks.

 

[mrblaine]

Perhaps you were sent the wrong shafts. I've never seen a set if shafts with what appears nuts to hold the u-joint caps on...

Just stop. Those are needle grease fittings. The hex is so you can screw them into the threaded holes in the caps.

 

[sierradmax]

my mistake.

 

[bjoneill]

The part with the arrow is part of the stub shaft. This pic is on the bench. No oil slinger right now.
I realize it is AlloyUSAs problem. I’m hoping quadratic will try to rectify, since that’s where I bought it and AUSA has been impossible to get hold of due to “covid”.
Tolerance stacking makes since.
But, how can I get the unit bearing to loosen up? Is it usually the stub shaft milling, UB fabrication?
These are the “Grande” 30 spline outer stubs. Will any 30 spline unit bearing work? I actually was worried about reusing them.
It seems my options are to completely start over, or try to patch together some version of new UB, or new UB and stub shafts.
is this correct ?
Thank you all for helping me out. Lessons being learned, the hard way.

 

[bjoneill]

Looking really closely at the pic and arrow it does appear to be a part on the stub shaft, and I will recheck when I get home, but I believe it is part of the milling.
IF it can come off it might allow the UB to slip on further.

 

[mrblaine]

The part with the arrow is part of the stub shaft. This pic is on the bench. No oil slinger right now.

It can't be part of the stub in that location. If it is a removable sheet metal slinger, then someone has found one that fits the smaller shaft diameter and installed it in the wrong place. If a slinger is used as a debris shield, it goes on the next shoulder towards the u-joint holes with the flange against the back of the UB to act as a debris shield. In normal use they were reversed and installed to carry a V seal against the back of a spindle. None of that really applies. In fact, the early TJ OEM shafts had them installed that way which renders them fully useless for any purpose except to sell slingers.

I realize it is AlloyUSAs problem. I’m hoping quadratic will try to rectify, since that’s where I bought it and AUSA has been impossible to get hold of due to “covid”.
Tolerance stacking makes since.
But, how can I get the unit bearing to loosen up? Is it usually the stub shaft milling, UB fabrication?

Not sure what you mean by getting the UB to loosen up?

These are the “Grande” 30 spline outer stubs. Will any 30 spline unit bearing work? I actually was worried about reusing them.
It seems my options are to completely start over, or try to patch together some version of new UB, or new UB and stub shafts.
is this correct ?
Thank you all for helping me out. Lessons being learned, the hard way.

Alloy USA is the only supplier of the 30 spline option. They are junk but you'll figure that out before long.

To solve your current problem without outside help, you need any 27 spline UB stub shaft swapped onto the u-joint and a stock UB.

 

[mrblaine]

IF it can come off it might allow the UB to slip on further.

Yes

 

[bjoneill]

The reference to “loosening up” was to something you wrote earlier, but you may have been referring to the UB literally loosening/coming apart.
What outside help are you referring to?
Im accepting that replacing the stub and UA with 27 spline parts may be the best answer. Are the AlloyUSA inner shafts shiite as well?
I thank you for all your help.

 

[bjoneill]

I finally got thru to q-tec. Complete waste of time. They did give me a phone number for Omix. It’s not a working number.
I will need new UB since the others were rusted the axle shafts. (What started this adventure)
What brands do you recommend, and who should I support/buy from. I know there is an Amazon link.
Many thanks

 

[mrblaine]

The reference to “loosening up” was to something you wrote earlier, but you may have been referring to the UB literally loosening/coming apart.

Yes, play in the bearings and races since they are moving away from each other.

What outside help are you referring to?

Omix, Alloy USA, or Q-tec fixing the problem with new parts. If you need to get going, any UB 27 spline stub and a OEM fitment 27 spline UB will get you on the road. Swap the stub onto the Alloy inner and go.

Im accepting that replacing the stub and UA with 27 spline parts may be the best answer. Are the AlloyUSA inner shafts shiite as well?
I thank you for all your help.

Depends on the day. Our issue with them was a total lack of consistency. Some broke at less than stock, some never broke even when they were worked hard.