Misc Is the AMC 20 Single-Piece Axle Upgrade Still the "Preferred" Method?

[iChuck12]

Good Afternoon, Ladies and Gents!
While in the process of restoring my '78 CJ7 QuadraTrac , I wanted to refresh the rear brake cylinders and de-rust the rest of the part on the rear hub/drums/etc. I encountered the common issue of not being able to get the hub off of the tapered axle (AMC20 with semi-floating tapered axle shaft). Took it to a shop and they couldn't get it in their press without risking the backing plate, so they loaned me a heavy duty three arm puller with a 3-ton hydraulic press built in. Tightened it on, snugged it up, then applied some heat to the hub where the splines are. The puller might have been a little too strong...



Looks like it might be time for a new axle.
Most of the comments I've read on this forum about replacing AMC20 shafts are older, but generally agree that the tapered shafts should be unceremoniously added to my local landfill after cutting the bearing and removing the backing plate, and replaced with a single piece axle & hub assembly.

Is this still the general consensus of the group at large?

I'm trying my best to take my time on this resto and get it as close to factory as possible (including trying to find an air injection pump and fittings). Will upgrading the axle to a single piece make a real difference in authenticity to the diehard enthusiast?

Any input/insight is welcome!!

Chuck

 

[Manic Mechanic]

Do yourself a favor and get a set of one piece axle shafts. Mine were so bad my machine shop had to use their 100ton press. It finally popped after cutting a slit and taking it over 30 tons of pressure. Sounded like a gun shot when it finally let loose

 

[CJ]

Moser or any one piece axle. Cannot say enough.

 

[iChuck12]

Do yourself a favor and get a set of one piece axle shafts. Mine were so bad my machine shop had to use their 100ton press. It finally popped after cutting a slit and taking it over 30 tons of pressure. Sounded like a gun shot when it finally let loose

Thanks for the advice. I've started doing my homework to make sure I find the correct set for the QuadraTrac . 30 tons of pressure; that's insane!

 

[TSB8C]

If you opt to keep the AMC20 with the Moser or other quality 1-piece shafts, make sure you get some top notch bearings to go with it. I installed 1-piece shafts with bearings from the local parts store and had bearing failure on one side after a few 1,000 miles. Ruined the new shaft as well. Ditched the Dana 20 and now have a Dana 489 rear end and love it.

 

[KRUPP]

Yup, as far as I know, one-piece shafts are still a preferred method if you want to keep the Dana 20 .
Our boneyard has a few discarded D20s. Heck, I'd give you one if you'd like , but I don't think any are the offset QuadraTrac type.

 

[iChuck12]

Yup, as far as I know, one-piece shafts are still a preferred method if you want to keep the D20.
Our boneyard has a few discarded D20s. Heck, I'd give you one if you'd like , but I don't think any are the offset quadratrac type.

Thanks for the offer KRUPP. I think I'm going to go with new one-piece axles on both sides with some quality bearings (Thanks TSB8C). However, a jeep boneyard sounds like a place I'd like to vacation!

 

[Manic Mechanic]

If you opt to keep the AMC20 with the Moser or other quality 1-piece shafts, make sure you get some top notch bearings to go with it. I installed 1-piece shafts with bearings from the local parts store and had bearing failure on one side after a few 1,000 miles. Ruined the new shaft as well. Ditched the Dana20 and now have a Dana 489 rear end and love it.

Cheap bearings

 

[TSB8C]

 

[Turbogus]

When my '78 CJ5 went squirrely with the rear one piece axles, the shop whose owner I was friends with contacted Randy's Ring & Pinion,
(Link)-> Ring and Pinion kits, gears, differentials | RANDYS Worldwide -<
and replaced the unknown axles with a set of Yukons, setting up the bearings was troublesome as the free play became an issue and trial and error failed us.



Ultimately, I decided to go with a rebuilt Dana 44 w/locker from Mac's Jeeparts (God Bless you Mac) and when we pulled to AMC20 out and got it on the ground we at last saw the trouble, the axle tubes were bent from the differential. This couldn't be discerned when it was mounted up.

 

[CJ]

When my '78 CJ 5 went squirrely with the rear one piece axles, the shop whose owner I was friends with contacted Randy's Ring & Pinion,
(Link)-> Ring and Pinion kits, gears, differentials | RANDYS Worldwide -<
and replaced the unknown axles with a set of Yukons, setting up the bearings was troublesome as the free play became an issue and trial and error failed us. View attachment 104684

View attachment 104685

Ultimately, I decided to go with a rebuilt Dana 44 w/locker from Mac's Jeeparts (God Bless you Mac) and when we pulled to AMC 20 out and got it on the ground we at last saw the trouble, the axle tubes were bent from the differential. This couldn't be discerned when it was mounted up.

Yep, the AMC20 axle shimming can be a pain...