AMC 20 Axle.

[jafo]

Ok. I have axle seals leaking diff fluid. I know almost nothing about their design. I've been looking at the service manual to get a better understanding. I understand that the one piece axle kits are the way to go. But, I don't want to install the new axle kit until I'm ready to put in the new carrier with new ring and pinion. So, that said, I'm just looking at doing seals for now.

My questions are, does the AMC20 utilise C clips to retain the axles? I didn't see C clips in the parts diagram. Can I just unbolt the end plate and slide the axles out and back.in? Also, looking at the diagram, it appears the seal is between the axle bearing and pumpkin. So I'm assuming that these bearings are lubricated with bearing grease?

I've never had one apart, so any pointers would be great.

 

[Peanut Butter]

I guess I'm kind of wondering why you don't want to use the new one piece axles. When making changes to a Jeep, it is best to do one upgrade or fix one problem at a time. If your doing a complete rebuild like I am that's a little different. So go ahead and put the one piece axles in. Your not going to hurt them. You will also be able to change the seal at the same time. When you go to do a gear replacement, the axles will pull out of the way very easy, then change the gears. Doing this will tell you if you have any problems with the axle swap before doing the gears. Now you are only chasing down one problem area. If you have a problem and you've changed both items, what do you look at first. Get what I mean. The axles are bolted to the axle tube, there are no clips to worry about. On the front axle in a CJ like ours, Dana 30 , the seals are closer to the diff than they are to the outside of the axle. The carrier must then be removed, and the seals punched out into the differential area. Se my build thread for pictures. I use a piece of pvc pipe to punch them out. I'm not sure where they are on the 20. Someone else may chime in on this. I haven't' taken mine apart yet, on the to do list.

 

[shum8]

I'm not sure where they are on the 20. Someone else may chime in on this. I haven't' taken mine apart yet, on the to do list.

They are out near the hub - between the bearing and punkin. Rear bearings are also lubed with bearing grease. I've often thought it would be nice to be able to install seals near the punkin similar to the front..... just didn't think about it hard enough to actually investigate the viability when I had the rear torn apart...... lazy, just lazy.

 

[HackFabrication]

My questions are, does the AMC20 utilise C clips to retain the axles? I didn't see C clips in the parts diagram. Can I just unbolt the end plate and slide the axles out and back.in?

From what I remember, and it's been over 20 years, the axles are only held in by the flanges. No 'C' clips.

Upgrade to the 1 piece axles. I had Moser axles put into my AMC20 when I had it re-done (4.56 gears and ARB locker).

 

[jafo]

One aspect is money at this point. Not ready to put money into the rear diff yet. Also, being that I am changing the gear ratio, the front will have to be done also. So I want to change out both carriers and ring and pinions in the same time frame. The other reason is I'm more familiar with GM axles and the axle bearings are lubed by the gear oil. I didn't want to put new axles and bearingings into a diff that could have junk floating around inbthe housing. The fluid in this diff was really low when I got it. No noises, but I just filled it up and have been driving it. The gears will be replaced eventually. So that is where my thought process was. I just want to change the seals to keep the goo off my wheels tires and garage floor.

That being said, I understand the rear bearings are lubed with bearing grease. How does this work out maintenance wise? They should probably be repacked every so often. So how often do they need repacked or regreased?

Thanks for the input everyone.

 

[shum8]

When I rebuilt mine, I installed zerk fittings in the axle tubes where the bearings live, and a #10 stainless screw 180 degrees around.





The theory is I can fill the bearing cavity with grease without removing the axle, and removing the screw allows pressure and extra / old grease to exit without blowing seals. Haven't tried it yet as the Jeep is still all aver the garage...... hate to admit it but the CJ I drove many years ago, I don't remember ever having repacked bearings. Never had issues, but was probly just young, stupid, and lucky. I'm sure someone will chime in with an intelligent repack interval.


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[jafo]

I sat down to go over in my head a plan of procedure to do the axle seals. Then I got to thinking, if you have the axles out, just do the bearings. Then it hit me in the head like a ton of "peanut butter"(pun intended). Then I just told myself to just bite the bullet and do the freak'n one piece axles and no more worries. So yes I'm listening, and you guys are right. Just put the one piece axles in and be done with it. I can always put the carriers and new gears in later.

So, one piece axles are the next upgrade. It will give me some piece of mind as well. I'm constantly worrying about those axles popping now that the bigger tires are on.

thanks again for the input and advice.

 

[jafo]

When I rebuilt mine, I installed zerk fittings in the axle tubes where the bearings live, and a #10 stainless screw 180 degrees around.





The theory is I can fill the bearing cavity with grease without removing the axle, and removing the screw allows pressure and extra / old grease to exit without blowing seals. Haven't tried it yet as the Jeep is still all aver the garage...... hate to admit it but the CJ I drove many years ago, I don't remember ever having repacked bearings. Never had issues, but was probly just young, stupid, and lucky. I'm sure someone will chime in with an intelligent repack interval.


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That's a neat idea. I don't think it will work with one piece axle kits though. I think those bearings are roller cage type bearings, all one piece. Can't think of the technical name for those bearings. But cool idea for the others. I'll bet it works great.

 

[shum8]

I have one piece axles as well. I packed them well before installation, so I figure before the test run (assuming I live long enough) I'll push as much grease in there as I can.


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[jafo]

I have one piece axles as well. I packed them well before installation, so I figure before the test run (assuming I live long enough) I'll push as much grease in there as I can.


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So how is the grease getting into the bearing assemblies? Is the grease being put in between the outer seal and the bearing face or did you drill a hole in the race? How does this work?

 

[shum8]

Grease goes in between the seal and the bearing - as the bearing heats up I figure being completely surrounded by grease will help keep the bearing full. Since its packed now, it shouldn't loose any as its used. I won't be able to force old grease out of the bearing this way, but I should be able to at least keep it packed. I also should be able to all but eliminate air pocket or the chances of water getting to the bearing


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[jafo]

Grease goes in between the seal and the bearing - as the bearing heats up I figure being completely surrounded by grease will help keep the bearing full. Since its packed now, it shouldn't loose any as its used. I won't be able to force old grease out of the bearing this way, but I should be able to at least keep it packed. I also should be able to all but eliminate air pocket or the chances of water getting to the bearing



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The bearinng should suck some in. It can't hurt having grease right there.

It is one thing I do like about a GM diff. That it always has lube due to the diff oil. They all have their weak areas and the seals are a weak area in any diff.

 

[Lumpy Grits]

Open diff '20' doesn't use 'C' clips.
The OEM, LSD version does.
Before you go to the trouble of rebuilding that '20'. Make sure the axle tubes and housing are straight and not bowed, or that the center housing has moved on the axle tubes.
If you do go with the 1 piece axle. I recommend Moser above all else.
LG

 

[jafo]

Open diff '20' doesn't use 'C' clips.
The OEM, LSD version does.
Before you go to the trouble of rebuilding that '20'. Make sure the axle tubes and housing are straight and not bowed, or that the center housing has moved on the axle tubes.
If you do go with the 1 piece axle. I recommend Moser above all else.
LG

Moser kit will be here this week.

It'll get checked. I want to weld the tubes to the center housing. I heard that is a weak point and welding was suggested.

 

[Lumpy Grits]

Make sure the welder understands he is welding cast iron to steel pipe.
Best to 'skip-weld' also.

LG

 

[jafo]

Make sure the welder understands he is welding cast iron to steel pipe.
Best to 'skip-weld' also.

LG

Got it.

 

[Turbogus]

Open diff '20' doesn't use 'C' clips.
The OEM, LSD version does.
Before you go to the trouble of rebuilding that '20'. Make sure the axle tubes and housing are straight and not bowed, or that the center housing has moved on the axle tubes.
If you do go with the 1 piece axle. I recommend Moser above all else.
LG

You siad a mouthfull LG, this was just what went on with 'Black Betty' early on and with the 20 axle mounted it was near impossible to discern that the axles tubes were bent enough to eat bearings.

It only became apparent after I had a Dana 44 built and the core 20 was laying on the ground out at Mac's Jeeparts.

God Bless you Mac, you're sorely missed.

 

[Ultrunner]

Open diff '20' doesn't use 'C' clips.
The OEM, LSD version does.
Before you go to the trouble of rebuilding that '20'. Make sure the axle tubes and housing are straight and not bowed, or that the center housing has moved on the axle tubes.
If you do go with the 1 piece axle. I recommend Moser above all else.
LG

Lots of discussion on the one piece conversion for the AMC20 . I intend to start this in the near future. What else do I need to get besides the Moser Kit? I don’t think it comes with wheel bearings etc... I’m doing an entire rebuild of the axle.

 

[jp360cj]

Lots of discussion on the one piece conversion for the AMC20 . I intend to start this in the near future. What else do I need to get besides the Moser Kit? I don’t think it comes with wheel bearings etc... I’m doing an entire rebuild of the axle.

The Moser kit includes everything needed to install (bearings, retainers, spacers, seals, etc). The only thing I think it doesn't include is wheel bearing grease.

 

[Ultrunner]

The Moser kit includes everything needed to install (bearings, retainers, spacers, seals, etc). The only thing I think it doesn't include is wheel bearing grease.

Thanks, you just saved me from ordering the wheel bearings and seals separately. I'll let you know how the rebuild goes once complete. Do you have any specific lessons to share?