The Ford Barn - Columbia dis assembly

I don't know the original author (maybe John Deats?) on this but this is what I used when I reassembled my Columbia and mine works well.

HOW TO PROPERLY SET UP 1928-1948 FoMoCo and COLUMBIA REAR
AXLE ASSEMBLIES USING THE GASKETS AS SHIMS.

1. CENTER SECTION.
A. Remove. pinion from actual center section with which
rear end will be built.
or
B. use another "empty" center section. Using a 3" to
4" micrometer, "mike" the width of this empty center
section and "mike" the actual center section with
which the rear end will ultimately be assembled.
Compensation for any difference in these widths will
have to be made later.
2. ESTABLISH TEE CORRECT "TOTAL" GASKET THICKNESS.
This gives the proper support or preload on the carrier
bearings and will later be split between the two sides
of the center section.
A. SINGLE SPEED REAR END:
Using empty center section, bolt passenger-side axle
housing to center section with no gasket and tighten
all bolts. Assemble axles, ring gear, carrier
mechanism, etc. and insert through center section.
Using some_arbitrary amount of gasket thickness
(say a .010" & (1) .006" or (2) .010" 's) bolt the
driver's side axle housing in place and tighten
all bolts.
or

B. COLUMBIA REAR END:
In a Columbia application the center section is
"sandwiched" between the ring gear and the planetary
assembly so the procedure differs from that for
a single speed rear end, but the principle is the
same.
Slip the Columbia side axle shaft through the
complete planetary assembly, then install the
Columbia spider cross with spider gears and
brass washers. Bold this up to the passenger's
side of the center section and bolt the ring gear
and driver's side axle to it using the 8 special
Columbia ring gear cap screws. Be sure the thrust
washer is betw~en the axle and the ring gear and
that the "ears" on the thrust washer are properly
engaged in the correct slots.
It is now arbitrary which side you choose to work
from to determine the "total" gasket thickness.
Personally, I prefer to bolt the Columbia carrier
casting assembly to the center section with no
gaskets and work from the driver's side as in the
instructions for the single speed rear end (see
above) •

then
c. Reach through the pinion-bearing bore in the center
section with your fingers and attempt to pull the
ring gear around by hand. NOTE: Use a screwdriver
or pry bar to move the ring gear the first quarter
turn each time in order to get the bearing rollers
to "seat."

WARNING: In the event that you have too much gasket
thickness at this stage, the ring gear will spin or
at least coast and there is a very real danger of
pinching your fingers badly between the ring gear and
the center section.

BE CAREFUL: Don't attempt to pull
the ring gear with your fingers until yo~ have checked
it first with a screwdriver or pry bar.

When you have the correct "total" gasket thickness,
you should be able to pull the ring gear around one
full revolution (one or two teeth at a time) with a
substantial amount of effort using only your fingers.
If you can't pull the ring gear around by hand, you
must increase the "total" gasket thickness used. If
the ring gear turns too easily or spins, you must
reduce the "total" gasket thickness. Remove and
replace the driver's side axle housing as many times
as necessary to change the "total" gasket thickness
until you can just barely "tug" the ring gear around
by hand one full revolution after moving it the first
quarter revolution with a prying tool each time.

Just for the purpose of some examples later, we will
arbitrarily say that the correct "total" derived by
this method turned out to be .026".

D. DISSEMBLE ALL PARTS FROM CENTER SECTION

3 . FINAL ASSEMBLY (or splitting the "total" gasket thickness
between the 2 ·sides of the center -section).
A. INSTALL PINION AND PINION BEARINGS IN CENTER SECTION
and preload
or
Switch the "real" center section with pinion in it for
the empty center section. You will have to adjust the
total gasket thickness arrived at earlier by any
difference in the widths of the center sections as
measured and recorded in step 1-A.
B. ESTABLISH BACK LASH BETWEEN RING GEAR AND PINION.
(NOTE: With genuine Ford ring and pinions and genuine
Timken bearings the gasket between the driver's side
the center section has always worked out between
~ .006" and .010" in my experience). The passenger's
side must be assembled first. Subtract .010" from
the "total" arrived at earlier and put the balance
on the passenger's side of the center section and
assemble (e.g.: .026" total minus .010" equals .016";
put a .010" and a .006" on the passenger's side).
After assembling passenger's side housing to center
section put the .010" gasket on the driver's side and
assemble. Grab the pinion by its splines and rock
back and forth with wrist action. Listen and "feel"
for backlash between ring gear and pinion. If you
get no backlash with a .010" gasket on the driver's
side, something is wrong.

Now do it all over again but this time plan to use a
.006" gasket on the driver's side. Subtract .006"
from your "total" and put the balance on the passenger's
side and assemble (e.g.: .026" total minus
.006" equals .020"; put 2 .010" gaskets on the
passenger's side). Now assemble the driver's side
using the .006" gasket. Again grab the pinion by its
splines and "rock" it back and forth. Listen and
feel for backlash again; there should be less than
before. If you ·get the distinct sensation that backlash
still exists between the ring and pinion, then
this "split-out" is acceptable for final assembly.
If there is no longer discernible backlash, you will
have to go back to the .010" gasket on the driver's
side and the lesser amount of gasket(s) on the
passenger's side.

As a final step, the housings should be removed from
both sides one last time and gasket sealer applied to all mating
surfaces and between all gaskets. While you are at it
coat the threads of all the bolts {"cap screws" if
you prefer) with gasket sealer and "wrench" things
together for the last time. Your rear assembly should
be ideally set-up and between the use of superior
gaskets and the gasket sealer should never leak the
first drop!

NOTES: Once you have determined the correct "total" gasket
thickness, this "total" should be maintained within plus .
or minus .002" when dividing the total between the two
sides of the center section. If in the examples previously
given, you had replaced the .010" gasket on the driver's
side with a .006" gasket without a compensating change
on the passenger's side, you not only would not get the
proper backlash*, you would have overloaded {"over squeezed")
the carrier bearings which would lead to
excessive wear and premature bearing failure.
Conversely if you make changes that add to the "total"
thickness by more than the plus or minus limits just
stated, you remove the preload on the carrier bearings