Re: [MV] Adjusting the drive pinion for axles on MB 1943

Lee Ethridge (
Thu, 4 Dec 1997 08:28:43 -0600

>I am trying to locate a "pinion setting gauge" to adjust the drive
pinion of both axles because
>one was badly due to broken bolts. I found them like this when i
bought the jeep last year.
>At the moment of bought I though they were ok.
>(Cfr TM-10-1513 p 1100-97)
>a. Can sombody help me in locating that tool?

>b. Once I have this tool in the above mentioned book they speak about
> a micrometer with the tool. On the figure I do not see a micrometer
to be used
> their is only shown how to put the gauge.
>Could somebody give me some advice in how to replace the pinion and
>differential and how to adjust them to the proper setting ?

I'm in the process of doing the same. I just collected some advice
from my father-in-law about this, so I'll pass it along.

This will be a general method for replacing and adjusting pinions and
ring gears without the use of special tools. (you should be able to
get by with feeler gauges, and maybe a runout gauge) Check with your
favorite repair manual and use your own brain to figure out how much
of this information is applicable to your situation. I haven't tried
the method I will describe here, but I will be using this method in a
couple of weeks to finish the rear axle work I've just started. It is
the method my father-in-law has used for the last 50 years.

Remove the differential. Leave the pinion in place.

Find a couple of pieces of smooth, straight metal. (Key stock is
recommended.) One piece is to span the back of the differential
housing and rest on the surface that the differential cover bolts to.
The other piece is to be clamped onto the first piece so that it
touches the end of the pinion gear shaft. Remove these
pieces without unclamping them and put them in a safe place. This
will be the gauge you will use for measuring the pinion pre-set depth.

Now remove the pinion gear, but leave the bearing cups in place. Make
another gauge like the first one and use it to measure the depth to
the top of the bearing cup nearest the pinion gear. (If you're
replacing the pinion, this measurement probably won't be that useful,
since what you really want is to achieve the same initial pinion depth
as the original pinion, with an adjustment applied to compensate for
the differences between the two pinions.)

Pinions and ring gears come as sets for a good reason. Never use a
pinion from one set with a ring gear from another set.

Adjust the spacers (shims) behind the bearing cup until the new pinion
rests at the correct initial position as indicated by the first gauge
you made.

Don't install the new collapsible spacer yet.

Install the ring gear on the differential carrier and install the
carrier in the housing. Add shims to eliminate sideplay. Start with
an equal thickness of shims on each side.

Blacken the ring gear and pinion with lamp black, apply resistance to
the back of the ring gear with a pry bar and rotate the pinion gear so
that the lamp black is rubbed off where the gears mesh. Adjust pinion
depth and ring gear spacing until the pattern made by the meshing of
the gears is centered.

Is this making sense? I'm going to give up now. I don't think I can
write an adequately detailed description of this in a reasonable
amount of time. Hopefully, now you see how the pinion depth setting
tools can be eliminated. Understand that you can't expect the initial
setting to be correct, and you will have to change shims, and
disassemble and reassemble until the gear pattern shown in the lamp
black or Prussian blue, or acrylic paint or glue or whatever you use
as an indicator shows a proper and well-centered pattern on the gears.

A trick I heard about years ago was to get two sets of bearing cups
and machine a little bit off the diameter of one set of bearing cups
so that they could be installed and removed easily. You would then
set and adjust the pinion and ring gear with these bearings, and then
remove them and install the full-size bearings before the final check.

Good luck, and don't take my word for anything. Check with a good
repair manual and be sure you understand it before starting.

You might even want to wait until I've done the procedure I'm trying
to describe and ask me about it then. With any luck, though, someone
else here can do a better job of describing this process and correct
any errors I've made in the description.


To unsubscribe from the mil-veh mailing list, send the single word
UNSUBSCRIBE in the body of a message to <>.