AMC 20 rebuild and 1 piece axle conversion

[KButler]

Hi there, I have a 1980 CJ7. It has ACM20 rear end with .273 gears, both by stamp on the axle and by counting, so I assume they are original. I've had the jeep for a year. This is a driver more than a trail jeep, and will eventually become a daily driver with light trail use. Nothing major. It has 305 sbc, Dana 300, and SR4 tranny.

Everything is leaking out of the rear axle. Pinion seal, rear diff cover, and both axle seals. I am converting the rear axles to 1 piece. I have removed the rear diff cover, and both axles. Drive side axle has pock marks where the bearing would be, passenger side does not. Both axle tubes have a fair amount of road crud inside of them. 1) Is there a good way to clean the tubes without taking out the diff? 2) Are there seals on the inner tubes I should be replacing while I'm this far? 3) I'm concerned the pocking on the driver side will keep the axle end from sealing, is this correct? Lastly, am I creating more problems by not just removing the entire axle at this point and working on it outside the jeep? I've never done work like this before, but I'm not afraid of it either. I do have a shop press and most if not all of the tools I need.

I've uploaded the photos and they are not oversized, but for some reason, when I click on 'insert image' just a box with a question mark comes up... no pic.

Thanks everyone.

 

[Ultrunner]

It’s tough to tell without seeing photos. But I just did all you mentioned and a little more. I would recommend pulling the axle. You will want to replace the inner seals once you are ready to install the one-piece.

I did a Moser Engineering kit. Also, with the axle out you can weld the tubes to the housing. They’re just pressed in right now. It’ll make for a much stronger unit once all said and done. I also did a disc brake conversion, but not everyone wants to go that far.

Are you planning on changing your ring and pinion ratio, getting bigger tires? If so now’s the time. You’ll want to replace all the bearings inside if you do, but if you’ve got all the tools and are not afraid of the work you’re fine.


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[Patrick]

You are off to a good start with the right tools and confidence, and asking around for advice.

Similar to rebuilding an engine with a good reusable block, you must determine if your axle is a keeper. Take it out and bare it all. Look it from a fair distance from one side down the inside of the tubes, similar to aligning a target with the optical sight on your thirty ought six rifle. Check for concentricity from end to end. Depending on your taste, you might tolerate a certain amount of non concentricity. Non concentricity means the axle housing is bent.

If a keeper, then the next steps should be a very thorough inspection, clean, paint, and careful reassembly. Of course, replace all seals and maybe bearings. Any extra upgrades are up to you. Good luck.

 

[Scout1067]

I am very curious how this works out because I am looking to do tje same thing in the near future.

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[RiverandSand]

I installed the G2 Axle & Gear one piece axles. They use set ten bearings if they need to be replaced. If you plan on a regear, you will have to do the front also to keep the ratios the same. Its a good time to think of installing a locker or a LS carrier too.