My waggon has been on jackstands 2 months waiting for weather to get above 45
so I can finish rear wheel bearing install.
Trubble is, as I wrote before, gotta redo brake linings, wheel cyls, et al.
BUT
Almost worst is the rear axle clearance specs, and the backing plate shims.
Note when I removed the right drum I found almost 3/16 clearance compared to
almost minimum required.
WHY
The rear axle bearings do NOT get pressed in place to seat against the flange
inside the rear axle housing. NOT.
Instead, a procedure must be followed that will rear axle bearing assembly and
axle (since it is pressed onto the axle) to be located BY THE RACE THAT IS
PRESSED INTO THE AXLE HOUSING and that race does not get pressed in until it
seats- the race must be set back a certain distance and the installation of
the backing plate and shims push the race (and axle with its bearing) into
place, allowing a hidden thrust block in the differential to be centered in
the differential!!!!!!
My 56 Ply shop manual does not (again not!) have detailed info on setting the
axle shim clearances.
However my 55 chrysler manual does.
so--
there is a hidden thrust block inside the differential that is supposed to be
centered on the pinion shaft axis, all of which cannot be seen! If one seats
say the left outer rear wheel bearings, against the recess in rear axle and
buttons up the assembly, this moves the thrust block to its maximum right
position (it is pushed there by the left axle itself). Now when you install
the right axle, since the entire left axle/bearning/hub assembly is tight in
place, it cannot move back to the left. Now the right axle has NO adjustment
possiblity and your axle/bearings cannot be adjusted- and the thrust block is
not centered but forced to ride on the end of the left axle.
Solution?
U can start from eitehr side, lets use the left.
One basically installs the outer bearing DRY to the recess (only for
measuring), and you Measure the distance the race sits in relation to the
outer face of the axle housing. Distance should be between one and 3
sixtyfourths of an inch. This measured inset distance is then subtracted from
.125 which is half the total distance the thrust block (it is slotted) can
move. Said remainder is the thickness of shims required on the left backing
plate. Now the race, axle with its bearing assembly are removed and the
bearing lubricated with wheel bearing grease. The axle and bearing are put in
place and the bearing RACE is tapped into place with a 2" + diamater pipe (I
used PVC plastic with a pvc sleeve on, it worked fine).
BUT BUT BUT
Do NOT drive the race fully into the axle housing, it should be left
projecting a distance greater than your calculated shim thickness SO THE 5
BOLTS HOLDING THE BACKING PLATE ON will slowly press the race in place!!!!!
Tighten the nuts a turn at a time alternating like when U install wheel lug
nuts. This action will press the race in place only to a preset depth (set
by the shims), your race AND BEARING will be slightly beyond the face of the
axle.
Now one moves to the right side, installs axle and bearing assembly dry WHILE
SOMEONE TURNS THE LEFT AXLE so U R sure everything seats. Now the right
bearing clearnace is measured. Measure as before but add .003 to the
measurement.
Remove axle and bearing, race, lube bearing, reinstall, leaving race
projecting beyond face of axle. Install backing plate with shims as
calculated. Use a dial indicator to measure the installed axle end play,
securing the base of dial indicator to backing plate and the pointer on end of
axle, and attempt to pull axle in/out. It should be between .003 and .008. If
it is not, add or subtract shims to correct. Theoretically shims shold be
adjusted both right and left side but my gut tells me you will only be a few
thousands off and adjustment can be made on right side only.
LATER YEARS Mopars---
I believe they use a special adjuster piece to set the clearances. However
there is a manufacturer called Green (Greene?) that has a special bearing that
eliminates the need for most of this for Mopars after what, mid 60's? Maybe
also for the full run of FULL finned mopars (57 on?).
All in all the procedure is not overly complicated but requires tools,
patience, an understanding of what U R doing, and above all a shop manual with
a complete description of the procedure.
as always
Rotsa Ruck
Lars
FYI I had to make additional shims of brass stock, hardware stores have same
4" wide and .010, 015 and maybe 030 thick. Used old shim as templete and cut
with a sabre saw, filed to finished size. Stock shims included 030, 0125,
010, 005 but cannot be obtained.
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