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Help! Burning up axle bearings.

E

eyesautomatica

Basic User
City
Bloomsburg
State
PA
Hey guys, need some genius advice here...

84 scrambler with AMC 20 rear end w/ Detroit locker, Moser one piece axles.

Took her in for an inspection and was told I needed to replace outter rear axle seals. This was after 6 or so years of mostly sitting after the one-piece swap (done by a previous owner). OK, so I pull the axles, swap the seals AND bearings because you have to cut the old bearings off to get at the seal.

Drive her maybe 5 miles to the inspection shop and something starts making a loud squeaking noise. Pulled up and my passenger side bearing is toast. Smoking hot, it is done for. I think, "I'm new at this, maybe I didn't press it on enough. Also, used set 9 bearings from a local parts store.

Second time around I mean business. Order Moser's replacement kit with timken bearings and had an experienced hand helping. Same deal. The bearing rollers were all flattened... Leaving me thinking this thing is getting too much pressure from the backing plate.

Third time we figure when we tighten down the backing plate, we use shims to relieve this potential pressure on my bearing. Shimmed it .008 total. Guess what? It just cooked.

I'm racking my brain trying to find an answer. She drove fine before any of this mess. I ran it often at night when no one could see my outdated inspection. This leads me to believe there is no bending I'm the shaft or housing. Am I simply not adjusting my preload enough? The instructions from Moser say to grind the inner ring to account for preload... But that is all in tact from the first Moser bearing/seal.

What the hell is happening? These bearings are cooking just taking it around town to test it. Top speed about 40mph.

Thanks y'all!
 
Did you check the bearing "stick out" with a feeler gauge, or did you just eyeball it?
 
It was an eyeball, yeah. But the max distance of .08" is 2mm. It couldn't have been out that far. On the bearing is a race and a round clip. It seems from the damage that clip is hanging it up. Is that piece necessary when pressing on the bearing?
 
eyesautomatica said:
It was an eyeball, yeah. But the max distance of .08" is 2mm. It couldn't have been out that far. On the bearing is a race and a round clip. It seems from the damage that clip is hanging it up. Is that piece necessary when pressing on the bearing?
Click to expand...

Need a picture.
 
Tag for more info.

I've got my 1 piece axles pulled to put in a locker, and was planning on just repacking the bearings and bolting them back in. Now you've got me all worried.
 
What do you want a photo of? It's going to be a week before I can get new bearings in the mail. Haven't pulled the cooked one yet, but I'm sure it's coming out in pieces. Have the other melted ones here.
 
eyesautomatica said:
What do you want a photo of? It's going to be a week before I can get new bearings in the mail. Haven't pulled the cooked one yet, but I'm sure it's coming out in pieces. Have the other melted ones here.
Click to expand...

I need to see a picture of the clip you were asking about, and where on the axle shaft/bearing it was.
 
Just talked to Moser. They are sending me a pre sealed, one-piece bearing. They said that it doesn't incorporate the outer or inner seal, and that you remove the spacer from the axle housing.

So this new bearing coming on Friday should press on after the backing plate and then you drop it in the housing. No measuring preload or anything.

Sounds strange to me, I don't understand the catch in this design... But I'm willing to try anything at this point.
 
You are pressing the bearing on the axle first, then the press ring after the bearing has been fully pressed on, correct? Are you installing the bearings with the correct orientation, which side of the bearing faces the wheel flange?
 
The instructions said in bold to press the bearing and ring on together, which I did. Definitely didn't mess up the orientation, the instructions from Moser are clear. From the axle end; seal, backing plate, bearing with larger lip of inner race facing splines, then the locking ring. The inner seal and spacing rings are already in the axle housing... Then the outer race of the bearing fits in against the spacer. For the potential of the outer race moving, used a friction enhancing substance and it was definitely in tight.
 
Sounds like you installed them correctly :thumbsup:

I always press the bearing on fully first, then the lock ring, but that's just me:twocents:


If the bearings are lubricated, the race isn't spinning in the housing bore, and the bearings are pressed all the way on the shaft correctly, I don't know what else to suggest??????????

Are the brake backing plates bent/bowed out in the center?

After you install the first axle, then go to bolt the other axle in, does the bearing go almost all the way into the housing, or are you having to "pull the axle in" with the brake backing plates?
 
Everything slid in just fine. The only thing I can think is that the bearing was sticking out of the housing too far. When the ruined bearings came out, the rollers were all rubbed flat on one side, as if something was preventing the bearing from spinning.. Because of too much pressure tightening down the backing plate.
That's my thought, but I did try shims, and all of these parts were from Moser. Everything was fine before trying to replace these seals... Nothing should be different.

Did you see my post above about the one piece bearings?
 
eyesautomatica said:
Everything slid in just fine. The only thing I can think is that the bearing was sticking out of the housing too far. When the ruined bearings came out, the rollers were all rubbed flat on one side, as if something was preventing the bearing from spinning.. Because of too much pressure tightening down the backing plate.
That's my thought, but I did try shims, and all of these parts were from Moser. Everything was fine before trying to replace these seals... Nothing should be different.

Did you see my post above about the one piece bearings?
Click to expand...

I ran a 1 piece ball bearing on some Moser shafts years ago without any problems. But, they still had to be greased and used the factory inner/outer seals.
 
Yeah, my new ones are coming in today.. He wouldn't sell me a new seal with this bearing.. But did say I should use the retainer plate from my worn seal and to cut the old seal out. I'll post my progress.
 
eyesautomatica said:
Yeah, my new ones are coming in today.. He wouldn't sell me a new seal with this bearing.. But did say I should use the retainer plate from my worn seal and to cut the old seal out. I'll post my progress.
Click to expand...

Be interested to see that. I have some retaining plates that have grease zerks in them, but the seals don't look like something that can be replaced.

IMG_3198.jpgIMG_3197.jpg
 
Have you removed the diff cover and inspected the gears and carrier? There should be NO reason you're eating up axle bearings. Something else is wrong. With a locker you need to check that there's no block between the ends of the axle shafts. There should be an empty space in that the two axle shafts do not touch. After that you check the lateral play and shim as necessary.
 
The sealed bearing fixed it up for me. She's running great.

I'm certain that I was not measuring for preload properly and cooking bearings because there was too much pressure on the side of the bearing when the backing plate got tightened.

My next project is going to be a 4.0 conversion on the head. Very excited to see the performance upgrade.
 
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