FULL AMC 20 rebuild and setup
Here I am (again)
Now for the AMC 20 setup...
So for AMC 20 you will need:
ring / pinion gear kit ratio ... 4.56 (ref 8134410 by SUPERIOR ref AMC456)
NB: I have NO action in SUPERIOR!
and a bearing kit and accessories (ref 35-2025 SUPERIOR)
-Bearings (of course)
-shims for the pinion detph and backlash
-Glue for cover seal
I think that's all!
Oh yes! A big nice SUPERIOR sticker !
First we ensure that the pinion and ring are well paired.
How we do this? Well as for the DANA 30 ... There must be a number engraved on the IDENTICAL pinion and ring ...
On the pinion:
Same number! So they are paired!!!
Those who have followed the rebuild of DANA 30 ... there is a problem ... on Dana 30's pinion there was also the pinion depth...
If you did not ... it's very bad ...
keep cool, SUPERIOR's guyz have tapered the pinion depth (RED) and the backlash (GREEN) on the ring
pinion depth 2.551 "(ie a +4 in old school style to the nominal pinion depth of 2.547") or 64.79 mm
Backlash is 0.006 "or 0.15 mm
Pinion depth , backlash, old-fashioned pinion depth ... it tells you nothing?
Ah! You can not even imagine that I redo the ALL course! not even DREAM..Everything is >>> HERE <<<
First BEFORE anything ...we need to remove the brake part of the OLD pinion nut in order to allow easy insertion during setup ...
So: screw, vise, wooden board (to avoid distorting the nut), and of course grinder and of course :APPROPRIATE PROTECTIONS:
and here it is:
We recovered now the old bearing cone inside of the old pinion to make him suffer too ...
the torture of the grinder ...
In the slit ... we insert a piece of steel for easy insertion / removal of the cone when installing the new inner bearing ...
Without it ... although the cone is cracked ... Is not a piece of cake...
Ready ? Set ? GO !
The pinion depth:
We need it all:
A Yoke whole fresh back from painting
A set shims,
A inside bearing: TIMKEN M802048 (cone) / M802011 (cage)
An outer bearing: TIMKEN M88048 (cone) / M88010 (cage)
A collapsible space for the preload
a NEW nut for pinion
and of course a new gasket seal.
We begin by setting the bearing cone on the pinion, we oil the part that will receive the cone bearing in order facilitate the integration ...
we installs the bearing in the right direction
And the interior cone that we have previously hacked ...
We add a BIG shim on the top of the pinion, and we press
when the manometer of the press raise ... it is time to release this little world ...
and we now proceed to calculate the pinion depth ...
First you need a ride on OLD pinion that had included this:
The last number is not very clear... Well, we will assume that it's a 1!
Go! it detailed! 34 is the number of matching with the ring that falls well: it is the same as the former ring:
and "+1" means 1/1000 of an inch over the nominal the pinion depth! 2.547"+0.001" = 2.548" or 64.72 mm
The old shim for pinion depth was 0.098" (2.49mm):
To be continued ... soon
Good topic that you make ! ;)
top notch wish i could do that! btw i can never get used to using latex gloves while working i always end up placing them on my head and acting like a 400 pound blue coned rooster
I had to move the Jeep to the garage because the owl wouldn't leave me alone in the barn.
stgil, thanks for this step by step! I'm getting ready to do my AMC20 also and this write up is just in time.
Thanks Guyz for your replies...
And back to the topic...
We know NEW pinion depth is 2.551 "(either a +4 in old school style (see above in the post)) or 64.79 mm
So we will have to reduce the thickness of shim 7 / 100 min of: 64.72-64,79 = 0.07mm is ~ 3 / 1000 of an inch!
We must reach a shim to be 2.49-0.07 = 2.42mm or ~ 0.095"
Here we have our available shims:
0.02"+5x0.012"+0.015" =0.095" or about ~2.41 mm it is not far from the right thickness!
So Rock'n'roll!!!: we install the outer bearing cup ... on the housing
with 68mm washer on the top of the cup and ...
few blows of mallets
we return to the differential housing to install the inner cup... first... we oil the machined part that will receive the bearing cup...
we install the shims... (2.42mm)
and then the inner bearing cup...
a washer of 82mm the top ...
and a pipe with 6mm diameter and 20cm long and then another washer ...
beat time and here's the result:
we ensure that shims do not move ...
We install the pinion...
We will install the other side of the inner bearing in the right direction ...
then the yoke...
and now, the OLD bolt (which has been hacked) ...
We install the immobilizer on the yoke...
To be continued ... soon...
and the nut must be tightened ...
... Until you get a slight preload 2-3Nm (or 5-6 kg ... see my DANA 30 post >>> HERE <<< for more explanation: I do not like doing things 2 times)
...5.5 Kg WONDERFULL!!
Back in the housing in order to set the pinion depth measure tool (I'll describe it in detail at the end of the post)
And the bearing caps (always well identified (right and left)) ...
Here it is the complete measure tool set ...
We set zero on the comparator gauge
we scoop the gauge under the fake axle...
Until the minimum value (do it many times the measure for consistency) ...
Well... we read -0.12mm
the block shim (on the top of the pinion gear) is 74.89mm, the nominal pinion depth of the pinion gear is 74.79mm (2.551") and the measurement read is -0.12mm
74.77mm not bad at all! it is 2/100mm (74.79mm-74.77mm = 0.02mm) from the ideal distance ... there is a tolerance or -5/100mm (0.002")...
So...It's all good! and at the first time!!!!
Easy isn't it? with the right way and the right tools!!!
To be continued... soon
differential bearing preload and backlash time!!!!
To do this, you will need:
-2 differential bearings: TIMKEN LM603049 (cone) / LM603012 (cage)
-8 NEW bolts for the ring
-A differential cage-limited slip littered (trac lok)
This cage was new (Crown Brand :mad:)... but I could very well could resume my old one... And finally I take the used one at last (I'll explain at the end of the post:( )
First we oil the machined part of the differential to facilitate reassembly of the bearings ...
We set the cage on the press and the bearing cone too... IN THE RIGHT DIRECTION
At end we set the OLD cone ... above ...
... and then a big shim ...
and now we press all together ...
when the press manometer raise up... we stop! ...
... seen on the ring side:
Back on the axle housing... where we remove the bearing caps (which are kept apart ALWAYS (right / left ))...
... then removing the measuring tools...
we install on the right a shim of 2.00mm thick ...
... left too (same thickness) ...
and we install now the differential cage with bearings...
And we install the bearings caps ...
To be continued... soon ;)
We tight the nuts...
We set the comparator dial so that the measurement is performed on the mounting ring ... we reset(0) the dialer while the plating on one side ...
and we push the cage to the other side (still dark :D ) ... and read ... 0.46 mm (we perform several SAME measure for accuracy)
That means putting a shim 0.01 "(0.50mm = 0.25mmx2) distributed equally on each side of differential
The fact that I put a little more (0.01 "(0.25mm) instead of 0.23mm) ... you'll see why ...
So we dismantled the right bearing caps ...
and left ...
and then we insert on each side a 0.01 "shims ... one side
and two ...
a short overview ...
We put AGAIN bearings caps, the comparator reset ... and normally ... if we push the cage the comparator should no longer move ... it's good ...
... And if you pull to the other side : it's the same ... it's all good: there is NO more gap...
We Dismount the comparator ... and ensures that when you turn the differential, we MUST feel a "slight bearing drag" that's why I put
a little more thickness of shims: 0.25mm instead of 0.23mm...
If it's no the case : add more shim on each side of bearing until you notice it...
Now we set AGAIN the comparator in order to measure the runout of the cage
The maximum runout should be 5 / 100 mm: I'm lucky : I have 3 / 100 mm with my old cage...
BUT the NEW CROWN cage exceed it : 16/100 mm!!! :mad: (see at the end of post for more informations)
when done ... we have to set the ring on the cage ...
We ensure that the support cage ring is clean ... otherwise use cloth and compressed air to remove dirt ..
we center screw holes and set NEW screw
and we tightened them to 75nm ...
... with the following sequence ...
Next step ... soon ;)
Both the right up of the DANA 30 and this on the AMC 20 should become a "sticky".
Well documented photos and lots of info with measurements that can be converted for the metric challenged when making tools.
Nice writeup!! Linked this thread in the CJ FAQ Sticky :thumbsup:
Many many thanks Guyz!!!:cheers2: :thumbsup:
I'm very happy that you like it...:thumbsup:
I've done much more post like this ...i.e. DANA 30 Steering, Steering column, electrical, and so on... on the French Forum...
But it takes time to translate (once again sorry for my English)
Next coming soon...
And back to the topic...
we shall put the shims (previously measured) in the housing ...
Then the differential (Be care full of the teeth of the ring and pinion gear and it is desirable to be 2 ...
... because the differential is pretty heavy, it would be nice to have 4 hands to hold in place the shims during inclusion of differential cage)
... then the bearing caps (always different) that is tightened to 110 Nm
Then we make sure that there is some slack in trying to turn the differential ...
It is not our case (no slack at all) So we dismount everything and removing a shim 15/100mm (0.006") (ring side)
to put the other side ... theoretically, the displacement of a 15/100mm (0.006") shim adds (or remove (depends the side
where you put the shim: in our case we ADD backlash)) a backlash of 7/100mm (0.003")
We put bearing caps (always properly torqued)
This time we have slack and we can install the dial indicator to measure backlash ...
Bad luck we have 12/100mm (0.005") backlash ... but we must have 0.006 " (0.15mm) (see above for optimal backlash (figure on the ring))
Note that the FSM do not worries about this statement: backlash should be between 0.12mm (0.005") and 0.20mm (0.008")
But we try to do this quite perfect...
So we move AGAIN (always in the same direction) a 15/100mm(0.006") shim to see if it approaches the 0.15mm (0.006") backlash ...
Bearing caps propelly torqued and so on... you begin to know how not? and again measured the backlash:
0.19mm (~0.007) Yeah not bad ... but could do better ...
We stop there (for now) for the backlash because now we have to add shims to the differential bearing preload.
10/100mm(0.004") shims on each side of differential cage . Hmm ... since we have a little too high backlash ...
I suggest you to add only 8/100mm (0.003") on ring side ...
and 12/100mm (0.005") on the other side (it always makes at total amount of 20/100mm (0.008") differential bearing preload)
we replace the differential ... WARNING: this time is a bit harder because the preload bearing is in place ... we should use
a lead hammer to finish setup:
... be carefull with the ring...
we tighten the bearings caps still 110Nm ...
and again we measure the backlash ...
15/100mm (0.006")! PERFECT!!!
Of course we must make several measurements around the ring and the gap between measurement should
not exceed 2/100mm! (0.001") : It's still our case ...
Guess what lies ahead?
yes! gouache time, there is one that has put his hand to the paw, or should I say truffle...
and here is the result which is PERFECT
This part is ONLY for control since we do the measure with the right tools...
Good! you know what ? ... we must remove ALL ...
to replace the interim shims by final shims in one piece ...
I'm TOTALLY agree with the Grear post ( >>> HERE <<<) : Shims delivered in the SUPERIOR
kit are weak and inapropriate: It must be replace with one piece shims (like OEM)
We must remove the differential cage ... Since there is a preload ... it's not easy...
FSM says to use large screwdriver (or a crowbar) and pull to remove it... It's not very safe for the teeth of the ring and pinion gear
So Here is my method (French touch):
a ratchet strap installed in the center differential is extremely tense
A few blows of lead hammer on the right and left of the housing ...
So you're now in LIVE time... I'm waiting for the final shims... hope soon!!!
where did you use the collapsible spacer? I thought it went in on the pinion to set bearing preload?
I do not use at this time the collapsible spacer... because I need to replace interim shims of the pinion depth and I need to dismount the pinion gear...
Collapsible spacer, yoke seal, yoke nut are 'one use purpose only':
If you set them and remove them, YOU NEED TO CHANGE them.
I'll use them when I'll do the PRELOAD PINION GEAR... be patient ;)
Excellent work. Thank you for taking the time to do these writeups.
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