AMC 20 1 piece axle fell out

[dtrojcak]

I've been googling for a few hours now and I have a few questions.
I have a 1978 CJ7 with a AMC20 rear end.
One of the PO's apparently did a 1-piece axle upgrade.
Last night, my axle started to come out of the tube. Luckily I was just leaving my brother's house and only going about 10MPH on his gravel road and not 50MPH down the highway. This apparently explains the very faint "metal rubbing" noise I mistakenly thought was the result of worn brake shoes.

I jacked up the rear end, removed the wheel/tire, and pulled the axle the rest of the way out.
Splines on the differential side look fine, no stripping/chewed splines, etc.
I then removed the 4 nuts and bolts holding the brakes onto the axle tube.
At this point I could see that some of the bearings were out of their "track" and sitting sideways compared to the others. The inner track with the slots that sits against the axle shaft was mangled and simply pulled out with a pair of pliers.
I then removed the rest of the bearings and the outside track.
From what I have googled/researched so far, this bearing assembly is pressed onto the axle shaft and this is essentially what keeps the axle from sliding out of the tube.
If that is correct, then I need another bearing, then I need to take it to a shop and have them press it down onto the shaft next to the hub.

My questions so far are:
Can I buy just the bearing or do I need to replace the entire axle shaft so they match?
If just the bearing, are they all the same size? If not, how do I tell what brand of axle shaft I have?
If I have to replace the entire shaft, can I do just one side, or do I need to replace both shafts at the same time?

 

[Scooter402]

I'm sure you'll get plenty of responses here, likely some with direct experience with the AMC20 rear end. I don't have direct experience with that particular axles, but many other models in general.

You can replace just the bearing, given that the area on the axle shaft where the bearing is pressed onto is still in good condition. You will also want to replace the bearing race inside the axle tube. They won't always come from the parts store as a pair, so make sure you get both. If there was no apparent galling around the axle shaft, there is no reason to need to replace it or have it machined. It may suit you to have the machine shop measure the bearing surface with a micrometer to make sure the interference fit is still acceptable.

Even with the aftermarket 1 piece axle shafts, you should (someone please correct me here if I am wrong) still be able to use the factory replacement bearings. If you have the one bearing cage removed and it is still round, you can measure it, or take it to the parts store with you to match it up with your new bearing.

On the other hand, you could install this bearing yourself, and not have to go to a machine shop to have the bearing installed. You can heat the bearing to about 250 degrees in the oven while the wife isn't looking, then borrow her oven mitt to hold the bearing while you drop it down over your axle shaft.

I'm sure you're planning on it, but when you get the new bearing and race, I'd replace the axle seal too. Hope this helps.

 

[dtrojcak]

So even the 2 piece axles have a bearing that needs to be pressed on?

 

[Scooter402]

Yes, it does.

 

[Kane]

Most aftermarket axles have a shrink sleeve inside of the bearing to retain both the bearing and axle. The bearing itself does not hold the axle in the housing. The axle manufacturer will sell this set together.

 

[dtrojcak]

I guess that brings up another question then.
How do I tell who the axle manufacturer is?
Is it stamped on it somewhere?
I didn't think about looking for that earlier.

 

[Purple77CJ7]

Moser Engineering Part CJTBK1/2 - Replacement Bearing Kit - Fits 1976 to 1986 CJ - 4 Wheel Drive

They all use the same bearing and seal sets. You can also get the bearing set and seals from NAPA. This is what I use from 4 Wheel Drive Hardware. It comes as a kit, since you have it apart just as well replace everything. To get the bearing off the shaft, you usually destroy the outer seal.

 

[dtrojcak]

Moser Engineering Part CJTBK1/2 - Replacement Bearing Kit - Fits 1976 to 1986 CJ - 4 Wheel Drive

They all use the same bearing and seal sets. You can also get the bearing set and seals from NAPA. This is what I use from 4 Wheel Drive Hardware. It comes as a kit, since you have it apart just as well replace everything. To get the bearing off the shaft, you usually destroy the outer seal.

I didn't have a problem getting the bearing off of the shaft because the bearing was destroyed and allowed the shaft to come out of the axle tube.

Thanks for the link. Now I have to decide if I want to get the parts shipped, wait 5-8 days for them to arrive, and then try and find a local shop that can press them in or make the 2 hour drive to one of 4WD.com's stores and have them press the parts onto the shaft.
I'm off on Mondays so I'm thinking road trip and get this done quickly.

Another question, is this bearing supposed to be packed with grease or does it get greased/oiled from the differential fluid?
The one I removed appeared to have no grease, which I'm thinking may have been the problem.
It was covered with differential fluid, but I'm thinking that was from the axle pushing the inner seal down/up when the axle started to slide out.
If it is supposed to be greased, then I'm concerned what the condition of the other side is.
I read somewhere about installing zerk fittings in order to make it easy to keep this bearing full of grease. Would this be a good idea?

 

[Lumpy Grits]

How chewed up is the bearing and retention collar area?
yes to the grease-There is an inner and outer seal to keep the grease in place.
Grease the bearing and put a handful in when you install the axle.
BTW-The bearing number should be stamped on the inner race.
LG

 

[dtrojcak]

Bearing is gone. The little cylinder bearings fell out everywhere when I removed the bearing.
I didn't realize there was another collar until this morning. It must still be inside the axle tube.
The jeep is not at my house, so I'll have to look at it later.

 

[Lumpy Grits]

Can you post pics of the bearing race area of the axle.
That axle may NOT be usable.
There should be a 'race' inside the axle housing.
Your say'n the axle bearing was ground all the way off the axle??
LG

 

[mtnwhlr]

I would be checking the other side if that side is that bad the other one may not be far behind. Better to find out now than on the highway. You may not get lucky twice.

 

[huntingbigun]

I just replaced both of my rear 1 piece axles bearing due to PO installing bearings backwards. Randy Pinions can hook you up with the parts you need. Should have seal plate on brake shoe side, brake plate, bearing and race then bearing keeper then a shim/spacer goes in the axles housing then inboard axle seal. The bearing was a Timken Set 9,

In the picture you can see the bearing (should point the other direction. then you see the bearing lock collar. You have to cut those off same with the race. No way to get a bearing splitter under the race between the brake plate. $80.00 each side will get you what you need, but as other said the inner race if it slides off by handle you may scrapped axle. Have to press the new bearing on and the collar.

Call Randys 1-866-631-0196

 

[dtrojcak]

Can you post pics of the bearing race area of the axle.
That axle may NOT be usable.
There should be a 'race' inside the axle housing.
Your say'n the axle bearing was ground all the way off the axle??
LG

The axle/brake/wheel assembly started coming out of the axle tube.
I had only driven about 100 yards when it started. When I shifted into 3rd and let out the clutch, I had no power. When I got out to look underneath, I noticed the driver's rear tire sticking out further than normal. There was about a 2-3 inch gap between the hub/brake drum and the brake shoe assembly. I jacked up that corner, pushed the axle/tire back into the tube, put it in 4wd and locked the front hubs and backed it up under a shade tree to work on the next day as it was already after 10pm.
The next day I removed the tire and then I was able to slide the axle all the way out.
I then unbolted the 4 bolts holding the brake drum assembly and removed it.
At this point, I could now see some of the roller bearings sitting sideways in the bearing. I was able to remove the inner race and bearings simply by swiping them with my fingers.
The inner race that is pressed onto the axle has a crack in it, which I believe is what allowed the axle to slip out.
It appears there is 1, maybe 2, more rings/races still in the end of the axle tube that I was not able to remove by hand or a screwdriver. It appears I need some sort of hook type tool to pull it out.
I'm not sure what would have caused the crack, but I'm thinking the shop that did the rear end work for the PO didn't pack these bearings with any grease. They are coated with differential fluid, but I don't see any signs of grease. The inner seal still inside the tube appears to be cracked/torn a little, which allowed some, but not enough, differential oil onto the bearings.
I pulled and inspected the passenger side and the bearing appear to be in good shape, but also do not have any grease, just some differential oil.
I drained the differential oil and removed the diff cover. The oil does not appear to be anything close to 90W gear oil. It is very runny/thin, almost like 5w-30w engine oil and very black. There was no milkiness, so I don't think it was water contaminated. Other than the thin oil, the diff gears all look clean and in good shape. There were no metal shavings or anything other foreign material in the oil.

I would be checking the other side if that side is that bad the other one may not be far behind. Better to find out now than on the highway. You may not get lucky twice.

I was thinking the same thing. Other than no grease, the passenger side appears OK.

I just replaced both of my rear 1 piece axles bearing due to PO installing bearings backwards. Randy Pinions can hook you up with the parts you need. Should have seal plate on brake shoe side, brake plate, bearing and race then bearing keeper then a shim/spacer goes in the axles housing then inboard axle seal. The bearing was a Timken Set 9,

In the picture you can see the bearing (should point the other direction. then you see the bearing lock collar. You have to cut those off same with the race. No way to get a bearing splitter under the race between the brake plate. $80.00 each side will get you what you need, but as other said the inner race if it slides off by handle you may scrapped axle. Have to press the new bearing on and the collar.

Call Randys 1-866-631-0196

Just so I understand you correctly, the bearings in this picture are backwards?
I didn't take a picture, but my passenger side bearings are the other way than your picture.
There is a collar that slides over the bearings on the small side next to the brake shield. When I pulled the axle out, the collar slides toward the brake shield about 1/8" or so, just barely exposing the rollers.
Does that sound correct?

Can someone post a picture of what it is supposed to look like?

 

[dtrojcak]

Forgot to attach pics
View attachment 17943
View attachment 17944
View attachment 17945

 

[huntingbigun]

That is correct the bearing should be large end pointing towards the carrier, this one is backwards as well the race should be pointed the other way, not sure about the spacer your talking about being on the outside of the brake plate. Should be just grease seal plate that 4 bolts go thru, you have to dig out the inner seal in the tube and then you can get a small 2 jaw gear puller to remove the bearing shim & race which is stuck in there after tour bearing failed. Your axle looks kind ok from the pic, kind pain to get the seal out and shim spacer should not be pressed in but mine were both stuck from the bearing being installed backwards.

In the pic you can see the race and axle seal also the bearing shim sitting behind the race.

Here is the instructions for Yukon axles, they were the same parts in my Genuine gear axles. It shows parts on the axle.

http://www.ringpinion.com/Content/ProductInstructions/M20%201-piece%20Axle%20Kit%20Instructions.pdf

 

[dtrojcak]

Thanks for everyone's replies.
I called around to a few machine/auto shops in my area and they all quoted me prices of around $60 to press on the new bearing.
I then learned that 4wd.com has a shop in San Antonio and Austin, which are both about 1.5 hours away from me.
They were the cheapest price on the bearings anyway, so I called them to ask for a quote on pressing them on.
I called the San Antonio shop this morning and after waiting on hold for 30 minutes, they told me they are all booked up for the next two weeks, but they could probably work in the bearing press if I brought the axle and dropped it off.
Then I called the Austin location and was surprised to have someone answer on the 3rd ring.
The guy told me they normally do not just do the bearing press on without the jeep there. They want to make sure everything fits correctly to insure no future problems and to validate the warranty.
I explained to him that the driver's axle was already out of the jeep and I would have to bring the jeep in on a trailer as it is not safe to drive. He said I could sign a waiver for them not doing the install and inspection, but I needed to be mindful of the proper spacer size to preload the bearings properly.
Tje San Antonio location never mentioned anythng about that.
I called the SA location again, and again I was immediately put on hold. After 15 minutes on hold, I hung up and called the Austin location again.
Same guy answered on the 2nd ring, and I asked him what the cost would be to fix my problem.
If I bring the jeep in, they will put new bearings on both sides for $100 per side, plus the cost of the bearings themselves.
I figured $40 extra per side for them to do the labor is worth it to me.
I wasn't planning on getting both sides replaced, but he explained that they rarely do on side only. It was highly recommended to do both sides at the same time.
It seems they mainly work on jeeps, so I'll feel confident they'll do it right.
Only problem now is I have to reinstall the bad axle into the jeep in order to load it on a trailer and haul it to them.
I'm still a little hesitant about allowing someone else do the work, but I cannot press on the bearings myself anyway.
So in conclusion, if my axle is still good, it'll cost me $333 out the door for the installation of two new rear axle seals, drain and refill the diff with new fluid, and inspect the axle for any other problems.
I am now starting to understand why everyone complains about the PO of their jeep. Sooner or later, you discover all of the shortcuts and mistakes they made.

 

[Lumpy Grits]

A section of pipe will install the bearing and collar.
That's how I've done all on my installs.
LG

 

[huntingbigun]

Any machine shop can press your bearings on, pipe trick works but I have a press so no big deal, new bearings, shim spacer, outer grease plates and inner grease seal 88.00 per side from Randy's, It is not hard to do just takes a little time to get the old seal out and etc. Good luck with your repair

 

[danray48]

A section of pipe will install the bearing and collar.
That's how I've done all on my installs.
LG

Did you heat the bearing first, then use the right size pipe to tap it in place? Also I noticed you were the only one to answer that the bearings are lubed with grease. I thought I read somewhere that you could install a grease fitting in there to keep it lube'd. Is that possible?