The Stovebolt Site Forums The Shop Area Engine Shop '40 GMC 3/4T rear axle spring perches

I got this email today:
I have a problem. I am restoring a 1940 ¾ ton GMC panel truck. I removed the caked grease and rear springs to clean and refinish. The springs are held on by a collet wrapped around the axle tube with u-bolts. Actually this collet is somewhat loose and is held in place on the axle tube by a half-moon key that is, I believe, riveted to the axle tube. My problem is that the rear end grease will drain out and around the rivets. This happened when the axle dropped down and became unlevel. I can't help from feeling this is wrong and refuse to continue this project until I find someone who knows my situation. I certainly hope you have the time and knowledge to help.

I have no clue what this fella is referring to. Anyone know?

My info indicates that an AC150 panel (yes GMC offered a 3/4 ton panel in '40) used a torque tube. The spring perches appear to be mounted in the same fashion as later year torque tubes in other trucks; part of the rear axel and not really removeable/serviceable.

Anyone had one of these apart that knows what this guy is trying to figure out? I'm lost.

It sounds like the part which is in contact with the axle-tube is wearing into the axle-tube itself.
_
-
On another note, it sounds like he is talking about the torque-tube going into the differential (per the rivets) :confused:

He's got a '40 GMC Panel . and he has a problem ?!?
Sounds like the spring carrier locating bit on the axle housing (that is rivited on) is loose and allowing the diff oil to leak out .
Or as Luke says , the axle casing may be worn thru and leaking ( same place).
I have fixed both problems , but really it is MUCH easier just to change out the axle housing for one in good condition.

Kook what dusty said is right , my 40 was worn not as bad, what they are called is spring seats, and after you get the spring u bolts off there are two screws that hold the seat to the axle, there should be a slight drag to them when fitted together, there is a grease zerk on each one to lube them, after years of no grease it eats up the axle housing, this guy has a severe case if it leaks rear end lube out at spring perches, time for a new tork tube rear end, the idea I guess is these seats allow the axle to move up and down with putting twist on the springs, and the key way keeps the axle from slidding left or right from under the truck., I welded 20 gage steel on mine to take up the slack, but am look for a new rear tork tube that isn't as worn on the axle perches, what I got will do for now, but will feel better if I know the first bumb I hit the axle outer housing isn't going to break. good luck

jbennett
40 burb