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model 20 answers

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1970390amx View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 1970390amx Quote  Post ReplyReply Direct Link To This Post Posted: Nov/04/2010 at 12:23am
Fuzzface your second picture clearly shows the outer seal. Its the flat plate with the lip on the inner edge, but the seal part is gone, its normaly bonded to the plate. I am in the process of looking for a seal that fits in that plate and has a different inner diameter to fit the moser axle.

Edited by 1970390amx - Nov/04/2010 at 12:51am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 1970390amx Quote  Post ReplyReply Direct Link To This Post Posted: Nov/04/2010 at 12:29am
After the axles are out all that is left is the ring and pinnion, and carrier. The caps are specific side to side and are marked up. I mark them with a stamp as to right and left also. I usually just use a center punch and mark one with one punch and the othe with two punches. With corisponding marks on the housing.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 1970390amx Quote  Post ReplyReply Direct Link To This Post Posted: Nov/04/2010 at 12:50am
Before removing the carrier I checked the backlash of this diff and found it to be about .010 of an inch. Spec is .005 to .009 and prefered is .008. This picture is for deminstration only, I had already started to pull the caps when I realized I did not take a picture. The bearing caps should be in place and tight to check backlash. Backlash is the space between the teeth of the ring and pinnion, and is measured by gently rocking the ring gear back and forth while holding the pinnion yoke still. after looking at this post I realized you can see the missing tooth on the lower of the two small spider gears 

Edited by 1970390amx - Nov/04/2010 at 12:53am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote billd Quote  Post ReplyReply Direct Link To This Post Posted: Nov/04/2010 at 6:37am
Originally posted by FuzzFace2 FuzzFace2 wrote:

Bill the bearings used with the Moser axles are sealed unlike the stock ones that you have to pack with greas like in your picture. I would have to pull the wheel & drum and that is not happening any time soon, to see if I used the outter seal. Here are some pictures I have of the retainer.
 
 
Dave ----


Yes, I realize they are sealed (on each side) however......... there's still a lot of crap kicked into that area, and sealed bearings, well, IMO, they don't hold like the original seals, and they do not seal between the bearing and housing!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote CR CRUISER Quote  Post ReplyReply Direct Link To This Post Posted: Nov/04/2010 at 11:20am
One of the critical steps that most people don't realize about the model 20 AMC diffs is that the axle hubs once installed must only be reinstalled on the axle shaft that they came off of.
 
When the hub was new (not previously installed) there were no splines cut into it. The hub splines are formed during the initial installation of the softer metaled hub being torqued onto the hardened axle splines. The position of the splines is determined by the small woodruf key. A hub can be removed and reinstalled onto the same axle shaft without a problem because the key aligns the splines.
 
If a hub is reused on an axle shaft that is not the original one that the splines were formed on, new additional splines are formed, the hub is severely weakened and subject to the dreaded spun hub syndrome. Always mark the hubs and axles before disassembly so that they are reinstalled as a matched set.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bcsideshow Quote  Post ReplyReply Direct Link To This Post Posted: Nov/04/2010 at 1:44pm
This is all great info.  I will be rebuilding mine this winter.  Any and all steps and pictures would be greatly appreciated.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 1970390amx Quote  Post ReplyReply Direct Link To This Post Posted: Nov/05/2010 at 12:26am
Originally posted by CR CRUISER CR CRUISER wrote:

One of the critical steps that most people don't realize about the model 20 AMC diffs is that the axle hubs once installed must only be reinstalled on the axle shaft that they came off of.
 
When the hub was new (not previously installed) there were no splines cut into it. The hub splines are formed during the initial installation of the softer metaled hub being torqued onto the hardened axle splines. The position of the splines is determined by the small woodruf key. A hub can be removed and reinstalled onto the same axle shaft without a problem because the key aligns the splines.
 
If a hub is reused on an axle shaft that is not the original one that the splines were formed on, new additional splines are formed, the hub is severely weakened and subject to the dreaded spun hub syndrome. Always mark the hubs and axles before disassembly so that they are reinstalled as a matched set.
Good points, I should have stated its standard practice to keep parts that are a press fit when assembled together. Although with  AMC parts getting hard to find I know of used axles and used hubs that are not matched being run together with no problems. I should have also stated any time you are using a puller or driving bearings you should be wearing saftey glasses. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 1970390amx Quote  Post ReplyReply Direct Link To This Post Posted: Nov/05/2010 at 12:37am
 using an inch pound torque wrench I am checking the pinnion bearing preload. Spinnig the pinnion with a torque wrench should yield a reading. Not the reading it takes to start turning the pinnion, the reading from a steady rotation after it has started to turn. This is a setup step that I under went to gauge the condition of the diff. Checking the backlash when I did also was to gauge diff condition. The preload was very minimal, about 2 inch pounds, should be 17 to28 inch pounds.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 1970390amx Quote  Post ReplyReply Direct Link To This Post Posted: Nov/05/2010 at 12:48am
I should have posted this before I showed checking pinnion bearing preload. Removing the carrier can be difficult. There is a preload on the carrier bearing as well, this makes it a tight fit. I will explain carrier preload in depth later. I use pry bar as pictured to nudge the carrier out. At the very outside egde of the cast part of the housing are two round holes. There is a speical tool called a differential spreder. I locks into those holes and will spread the diff apart so the carrier slides out. Never have seen one. A coworker used one in the army, and watched a truck diff split intwo with one

Edited by 1970390amx - Nov/05/2010 at 12:48am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 1970390amx Quote  Post ReplyReply Direct Link To This Post Posted: Nov/05/2010 at 12:50am
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