tbear,
I should have been more specific (and at the same time not described the tubes as being pressed in). The 360 degrees weld on the axle tube has been re-welded with an arc welder. It is obvious when compared to the near perfect factory weld on the right axle tube. I've never noticed until now that I have the entire axle assembly out from under my truck in broad daylight (with all the dirt and grime cleaned off). Whoever welded it did a decent job as far as looks go, but it has me concerned that they likely did not have it in a jig and you know how steel reacts to heat when you go to welding on it. I'm unsure if it is aligned correctly or not. Maybe they noticed a slight break in the factory weld and decided to go all the way around it as a precaution....??

 

It's certainly possible that it's been rewelded I guess, but I'ld be surely surprised to find one that someone took the pains needed to do a complete 360 degree reweld there.
The welds on mine around the tube aren't quite as smooth as the butt welds along the seems either, but there's a step where the tubes enter the opening on either side.
And then I don't know if the original welds were robotic in the '70s or man done, but the long straight welds are easier for some than the round the tube welds.
Also, not uncommon for axle lube to seep at the vent tuibe fitting / hose and look like a leak.

Anyway .... one way to check it side to side is clean the tubes really good at two sides 90 degrees apart at least each tube (4 areas). Set the housing on a pair of stands and then level the left tube using shims under one side, and once level .... check the other tube. If straight in that plane, both will be level.

Then rotate the housing 90 degrees, like if the opening for the carrier was verticle before, make it level now .... and level the left tube again and once level, check the right .... both should be near level.

There is a slight tollerance allowed, even on new trucks, but I am willing to bet that if you clean the tubes surface good before slapping the level on and use a good level, you won't see a variation.

 

tbear, I know what you mean as far as the pain it would be to do a 360 weld in that location especially with the axle under the chassis, but it has definitely been re-welded at some point. When I compare the weld to the same location on the opposite (right) side, it is very obvious. You know what I'm talking about.....wide bead, slag left on the weld in a few places, etc. I'll take some pics soon and post. The weld looks strong, now I think I'll go through the process you described to make sure the axle is "true". Thanks, by the way, for taking the time to describe that. As I was reading it, I thought of another way that I could check it: If I took two 4' levels (or anything with a perfectly straight edge) and placed one on each side flat against the plate that the axle bolts to, then measure the distance between the levels in the front and then in the back, those measurements should be the same. I could then turn the entire axle housing 90 degrees and repeat the procedure. I can remember my dad doing this on other applications around the farm.

 

Like I said, it could have been rewelded, but I would be shocked if so.

Those plate you mention just hold the brake backing plates and a bearing retainer plate, they aren't necessarily square to the axle tubes.

If the pumpkin were mounted in the housing with a gasket between and the axles in place, you could mount a couple of machined allow wheels which tend to run true as they are machined to their mounting flange .... and measure straight acrossvarious places around. Steel wheels often have some runnout or maybe not, so there you'ld have to mark a spot on each wheel and make sure you pulled straight across.

Anyway ...... I'm sure you'll get it figured out easy enough. It's cold out, but I'l maybe get a pic of my '77's housing for you to compare?