AMC 20 Rear Axle Rebuild

While waiting on the frame to be finished I figured I would start on the rear axle rebuild which is an AMC 20.  This is the original axle.  While looking into rebuilding axles I found out that the term "If it ain't broke, then why fix it" comes into play with axles.  I decided not to mess with the gears.  For right now I am just going to get all the rust off, replace the drums and breaks, fix the pinion seal leak, add new gear oil, and paint it up.  Of course all of this can change once I dive into it.

I started with removing the wheels off the axle.  You can see by the bucket under the diff that the pinion seal is leaking.

Found out that one of the drums is broken.  I guess I will be replacing both of those.

I wanted to remove the drum to take a look at the brakes and all the other components. 

 I looked into sandblasting the axle myself with this small craftsman sandblaster and some play sand.  I went cheap with using the play sand as the media and realized after spending about 2 hours messing with it that it does not work that well.  I need to get some real blasting media if I am going to go this route.

Since the sandblasting did not work to well, I decided to put a wire wheel to it.  That put a huge mess in the old garage with all the dust I created.

Here are some during and after pics of the axle after I tackled it with the wire brush

I need to fix the pinion seal, so I figured the first thing to do is remove the diff cover and drain all the old oil.  Guess what I had to deal with again??? RUSTED SEALED TORX BOLTS.  Those damn things did the same thing as they did when trying to removing them from the tub.  When just trying to remove them they wold just strip out.  I sprayed PB Blaster on them for two days and then tried some heat.  It still did not work.

I solved the problem!!  I took a larger size torx bit (T-40) and jammed it into the bolt.  This gave the bit a good grip onto the bolts (which I plan to replace with hex head bolts)  With the good grip and the help from the PB Blaster they came right off!!

I got the cover off!!  I'm no pro, but it sure does look like the ring and pinion is in good shape.  I did not see a single break in any of the teeth.  There was some rust though and not much gear oil came out when I got the cover off.  My guess is the little bit of rust was caused by the low oil.

I took a low speed wire bush and cleaned off the old seal.

Here is the old rubber gasket that was on there.

Used this break cleaner to clean up as much of the old oil as I could.  I also took a towel and wiped out what I could.

Made sure the edge was nice and clean and dry.

I took this angle grinder and wire brush and cleaned up the inside of the cover.  There was a good amount of rust on this.  All nice and shinny now!!

I forgot to take a picture of me applying the new gasket sealer to the diff.  I used Ultra Grey.  I set a good amount all the way around the diff. 

I hand tightened all the new 5 grade hex bolts (could not find 8 grade in the right size).  I then let it sit for an hour, then torqued all the bolts down to 20 ft pounds in a cross pattern.  Lets hope it holds the new oil.

Next up is to tackle the pinion seal leak.  First step was to remove the pinion nut.  Before I tackled that I marked the position of the yoke, the nut, and the axle so that I can put it all back the way I had it.

The first problem I ran into was removing the pinion nut.  The two most used methods I found on the internet was to use the handle of a floor jack or use a pipe wrench to stop the yoke from spinning while taking the nut off.  Since I did not have a pipe wrench I tried the floor jack method, which I forgot to take a picture of.  This picture below is one I found off the internet of someone else doing the same thing.

THAT DIDN'T WORK.
When I torqued down on the breaker bar it bent the shit out of the strap and also broke one of the bolts in the yoke.

Since the floor jack method did not work, I went searching for a pipe wrench.  My father-in-law had a 2ft pipe wrench and a 4ft breaker bar that he let me borrow.  This breaker was no joke.  That thing felt like it weighed about 15lbs.
You can see in the next three pictures that I clamped the pipe wrench onto the yoke base while letting the other end rest on the floor to stop the yoke from spinning, used a tire to stop the axle from lifting up, and put all the weight I had on the breaker bar.  After doing all of that I finally got the nut off!!!

Next is to remove the yoke.  I went to AutoZone and rented this puller to help me get the yoke off with out damaging it.  The puller did not come with bolts that fit the yoke, so I pick up some at Agri Supply. 

I was able to get the yoke off with no problems.

Next was to remove the busted seal.  This was on there good.  I did not have a seal puller, so I just used a screwdriver.

The seal is made of a metal outer ring, and rubber inner ring, and a spring that sits on the inside of the rubber ring.  This picture is the rubber ring and the spring that fell out when I was hacking at it.

I used a pair of vice grips and a screw driver to pull the rest of the seal (metal ring) out of the differential.

I finally got it out after a bunch of pulling and hacking on it.  That thing was in there good.

 

After cleaning up some of the old oil I noticed that part of my jeep was made in Canada.  (What the hell??  I thought my jeep was made in the Ohio plant?)


I cleaned up everything the best I could and also removed the broken bolt out of the yoke with an easy out.

 I thought that I was going to have to replace the yoke but after cleaning it up, it looked pretty good.  There was a very very small grove on the yoke from the busted seal rubbing on it, but it was so minor.  I took some very fine grit sand paper and smoothed it out.  I will give it a shot.  If it still leaks, then I will just redo everything with a new yoke.

I put some grease around the outside lip of the new seal and gently put it back into the diff.

Using this block and hammer, I gently taped the seal as evenly as I could back into the diff until it was flush with the housing.

Using the marks on the yoke and the pinion gear, I placed the yoke back onto the pinion gear.

Again using my state of the art "4.4 leveler installer", a.k.a. 4x4 block, I gently tapped the yoke back on.

I purchased a new pinion nut and installed that back on.

After putting new oil in the diff I finished up!  Now I am going to let it sit for at least a day to see if it leaks.

The pinion seal did not leak but the piss poor job I did at sealing the diff cover was leaking.  This is all the oil that leaked out.

 I took the cover back off and wrapped the gears up with a paper towel to try and keep some of the dust and dirt out while cleaning it again.

 This is the inside of the cover after I scraped all the old RTV sealer off the edge.  All nice and clean again.

I used some break cleaner and made sure I got all the old RTV sealer and any dirt off the housing before resealing.

I used about a half of a can of break cleaner on the gears to make sure I did not leave any chunks of dirt or old sealer inside.  I took a towel and wiped it down too.


After putting a shit ton of RTV sealer on the diff I hand tightened the bolts down and let it sit for 24 hours.  After 24 hours I torqued each bolt to 20 lbs and filled up the diff with new oil.  I then let it sit for a week and it never leaked!!!  Lets hope it stays that way.

Now it time to give the axle one good cleaning to get it ready for paint.  But before I begin I removed the breather tube.  This tube was all cracked and beat up.

This is the breather hole after I removed the rubber hose.  You can see that it was clogged with rust dust.  Maybe this is the reason the pinion seal was leaking???
I used a drill bit and the shop vac to get the dust out.  It should be good to go now. (I hope)

I used some Simple Green, a flat head screw driver, and a small wire wheel that attaches to my drill to clean the axle some more.  I thought that it was going to be a quick easy job, but when I got to working on it it was a lot dirtier than I thought.  It took me about 1 hour of scraping, scrubbing, and crying to get just half of the axle clean.

I removed this bolt on both sides of the axle.  I took this picture just to remind me where it goes when I put it back together.

Here is the right side of the axle after I got it all cleaned up and called it a day.

After waiting a day, I got back to cleaning up the left side of the axle.  You can see in this picture that there was still a lot of dirt that I had to scrape off.

After getting the axle all clean and dry, I sprayed OSPHO onto the axle.  The guys at Cisco Built Rides recommended this stuff.   When OSPHO is applied to rusted surfaces, it resists/retards rust in chemical change on drying to a tough, hard surface ready for priming. A paint job will last longer after an application of OSPHO because subsequent paint coating securely attaches itself so that moisture and oxygen normally do not attack the metal.

The next four pictures are of right after I sprayed the OSPHO over everything.  That stuff stunk bad, but I would see it going to work immediately.  All the rusted spots started turning into a metal and black looking color.  I am going to let it sit for at least 24 hours and then maybe rotate it and spray some more on.

Because I had a lot going on, I ended up letting the axle sit for two weeks after I spayed that OSPHO on it.  There were a lot of white crystals and black stuff all over it which needed to be sanded off.

I tried using this sand paper that hooks to my angle grinder.  I did not like it that much because it only worked well on a flat surface.

I switch to the wire wheel to get off the dried up OSPHO criystals

Next two pictures are after I finished with the wire wheel.

Went over the axle again with some Simple Green to make sure it was nice and clean.

Next was to put a coat of primer on it.  I used this Rust-oleum primer.

Here it is.  My first primed part of the Jeep!!

I finished priming the axle after putting about 2 coats on it and letting it sit for 3 days.

I took a very fine grade steel wool and sanded the whole axle.

There were a few spots here that I had missed with the primmer.  This picture is after I finished touching it up.

After letting some of the primmer touch ups dry for another day I sanded the axle down again, cleaned it up with some soap and water, let dry, and started painting the topcoat.

I went with Rustoleum gloss black for the top coat.  From what I researched, this should hold up pretty well and not chip.

I got the first coat on the left side of the axle.  Its already starting to look pretty tough!!

Finished with the first coat.  It is about 97 degrees outside and a little humid, so I am going to let this sit for at least 48 hours before I put another coat on it.  Its nice to have a freshly painted part.

I let the axle sit for a week, then sanded it down with some 380 grit sand paper.

Finished applying the 2nd coat.  I think I am finally done with this axle.  The only thing left to do to it is replace the brakes, which can be done anytime.  

BEFORE & AFTER