AMC 20 Axle Woes. Need Help/Advice

[Techlight]

Hey All,

So my axle shafts move about 1/2 an inch to maybe 3/4 of an inch on both sides. This is on stands with tires off and I'm trying to figure out what the deal is and how to go about fixing it. The shafts don't seem to be broken. If I spin one side the other spends along with it and no scraping or difficulty turning them etc.



So here's the longer part about how I got here :

I had an ebrake cable fail (I swear it was on my long list of things to do) and I was a few miles from home. I found this out the hard way when I started smelling something weird. I pulled over and found my rear right tire pouring smoke from the heat etc because the brake was fairly locked. It would roll but with resistance. Fun times. Let it sit to cool off for about an hour and drove it home in first crawling along to try not and build up excessive heat. Kept pulling over to check how warm things were, no more smoking but still warm enough to worry me. Heard a few frightening pops from the axle maybe twice. Not a breaking sound, but sounded more along the lines of built up tension popping kind of sound (if this makes any sense).

Anyway, parked it and ordered all my parts to overhaul the brakes and ebrake lines (cables, drums, etc) and next day I noticed that my rear right tire extended out more than it's normal amount which made me question my body mounts until I took it apart and noticed the extremely excessive play on both sides (the rear left is leaking oil too now). It's been sitting now for a month...i've been too busy with work to get into it.

The axle nuts looked like they haven't moved and the cotter pins are still there (not broken etc), so I'm confused how it got to this point unless my diff is fried in some form.

So please chime in on causes/fixes/next steps/etc, I'm completely lost when it comes to overhauling axles and I've never had to work on one before so I have no experience (which is about to change haha). My future plan was to get one piece axles in there and just upgrade it and solve the problem all in one shot, but it's not in my current budget. I was kinda hoping it might be "cheap" to fix it up stock without too much trouble. But now I'm concerned about the diff and some part of me was hoping that I could band aid it so I can at least enjoy some of the So Cal weather I have here.

Thanks in advance...we'll see how many responses I get on good ole Valentines day

~James

 

[Lumpy Grits]

Moser 1 piece axles is the best fix. Every/anything else is a 'bandaid' at best.
Do the job 'rite'
LG

 

[hondo]

sounds like a axle shaft/ wheel bearing problem throw away the old ones and get some moser shafts.

 

[Techlight]

Thanks for the responses...I talked to my Jeep mechanic too. Luckily for me he doesn't mind if I stop by the shop and pick his brain. It helps that he was a Jeep tech in the 80's. His opinion was the same. Says the excessive play is probably from shot bearings and suggested I put in the one piece kit. Otherwise we could take it apart to replace the bearings and hope the races are still good, otherwise were approaching the cost of the one piece kit which comes with all the parts etc. I figure an extra few hundred to get it done right and have the one piece is the better way to go. I guess I was hoping I could throw a hundred and fifty at it and solve the "now" problem. If i spend the little extra now I'll have it done right with the upgrade I want and be finished with it.

So I guess I'll start saving my pennies for the one piece kit. I do have a call in to my local jeep boneyard since I have an inside track there. Who knows, I may come across a "cheap" AMC20 with one piece installed or find that fabled unicorn (Dana 44 ) haha.

Probably wont have my pennies collected until April'ish so in the mean time I'll just sneer at my brother when he drives by, since he already has the top of his FJ off and is seemingly mocking me whenever he drives past my house and waves

Thanks again...

 

[hdgapeach]

Sounds like you baked the wheel bearings.....and good!

I've had an axle run right out of the tube at 50 mph once and your comment about the tire sitting out further brought out that memory. Glad you didn't have to endure that ride with yours.

Make a point to check the axle tube bearing pocket diameter specs before you just R&R the bearings. I made the mistake of not doing that when mine went out on me and paid the R&R price twice !! Yep, too much slop in the hole, and the new bearings came apart. Ended up having to find a new axle housing before I could fix it right.

Man, ain't nothing like doing 360s on the highway with 3 tires in a CJ5 !

 

[Lumpy Grits]

No such thing as a cheap AMC20 with what they cost you in the end.
Bite down, and get the Moser's!
Yup-about to take the top off of mine too
LG

 

[Bent]

This site is starting to sound like a Superbowl ad for Moser.

 

[hagar]

If it were me I'd tear into it, inspect it, and just fix what's wrong.
Might be all you need are axle bearings and seals; and of course set the proper end play.
Make sure you invest in the proper size 1" drive socket and breaker bar to tighten the axle nuts to the proper torque.

 

[Lumpy Grits]

This site is starting to sound like a Superbowl ad for Moser.

That's because they work well and are the type of axles, AMC should have used.
That's what happens when the 'bean-counters' run a company--
LG

 

[Lumpy Grits]

If it were me I'd tear into it, inspect it, and just fix what's wrong.
Might be all you need are axle bearings and seals; and of course set the proper end play.
Make sure you invest in the proper size 1" drive socket and breaker bar to tighten the axle nuts to the proper torque.

Lipstick on a pig-
LG

 

[hagar]

Lipstick on a pig-
LG

If the one piece aftermarket design is better than sliced bread, why are all the Jeep forums full of threads about axle bearing/seal failures?

The AMC20 is an okay axle if you just keep the damn nuts tight; folks don't do the maintenance or beat the hell out of their Jeep; neither of which can be beneficial for your Jeep.

Now that OEM axles and hubs for the 20 will be hard to find, the Chinese junk tha's out there won't help the 20 reputation.
Once again, it's the operator not the equipment.

 

[Bent]

If you plan on any sort of differential swap in the future, you will need to swap to one piece axles anyhow. Anything except the stock open and trac-lok differentials will not have a thrust block between the axle shafts. This is a problem for the OEM shafts because the stock bearing arrangement puts the bearing inboard and the cup held down on it by the brake backing plate. If you use a differential without a thrust block, the axle/bearing can drift inboard enough to remove the preload on the bearing. One piece axles avoid this by using Timken set 9 bearings that put the cup on the inside and the brake backing plate pushes the bearing into the cup.

 

[Lumpy Grits]

If the one piece aftermarket design is better than sliced bread, why are all the Jeep forums full of threads about axle bearing/seal failures?

The AMC20 is an okay axle if you just keep the damn nuts tight; folks don't do the maintenance or beat the hell out of their Jeep; neither of which can be beneficial for your Jeep.

Now that OEM axles and hubs for the 20 will be hard to find, the Chinese junk tha's out there won't help the 20 reputation.
Once again, it's the operator not the equipment.

How about improper install be'n the cause of the failures.
It's not just 'tight-nutz'. It's that joke of a piss pour wanna-be spline design between the axle and hub on the POS 2-piece axle design.
I have installed over a dozen pr's of Moser's over the last 10 yrs or so, and never had one fail to date.
I also made sure the housing wasn't bent-
LG

 

[hagar]

How about improper install be'n the cause of the failures.
It's not just 'tight-nutz'. It's that joke of a piss pour wanna-be spline design between the axle and hub on the POS 2-piece axle design.
I have installed over a dozen pr's of Moser's over the last 10 yrs or so, and never had one fail to date.
I also made sure the housing wasn't bent-
LG

And I've seen 35+ years of stock 20's with ZERO failures.....when maintained properly. One still has the ORIGINAL axles and hubs from 1978, with a Supercharged AMC 304 under the hood.

So I guess we're both right....

 

[Lumpy Grits]

Blown AMC 304 should have twisted those tubes into pretzels.
Seen a stock 6 do it, with 37" tires.
All I know is my Ford 9", in the rear, is some of the best money I ever put into my Jeep.

LG

 

[Bent]

Blown AMC 304 should have twisted those tubes into pretzels.
Seen a stock 6 do it, with 37" tires.
All I know is my Ford 9", in the rear, is some of the best money I ever put into my Jeep.

LG

WHAT!!! You're not even running Moser one piece AMC20 axles? Now I really believe they must be paying you.

 

[Lumpy Grits]

WHAT!!! You're not even running Moser one piece AMC20 axles? Now I really believe they must be paying you.

LOL
No mo-20 for me.
Put my Currie 9 in about 23 years ago and never looked back.
LG

 

[Bent]

Alright then LG. But, if some kids asks about his gas cap or something, and you recommend he upgrade his axles, we'll know for sure.

 

[Lumpy Grits]

My gas cap has a leash on it. So I don't lose it, like I did my mind.

LG

 

[Fastatv]

I'm going to jump in here a moment.. I had the AMC two piece axles and I thought they were ok. I spent about $100 plus on new stock bearings, seals, backing plates ect....Thought I would be good to go. Had two problems later, and one of them was due to age I think. I spun the left rear axle in the hub. And I believe this was due to age and rust. After the hub spun, further damaging the splines on both axle and hub, I temporarily welded the hub to the axle. Next drive out, snapped that same axle in to.. At that point, I went with the Moser one piece axles which I should have done to begin with. Now, I'm not saying the AMC20 is a bad axle, but I am saying that age...rust, 38 years in use and such was something I wish I would have considered in the beginning.