I’m going through the rear end on a friend’s 67 and we’re trying to keep it as original as possible while giving it a thorough rebuild.
All the major parts look good except for maybe the stub axles and I’d like to get some guidance from the experts here on how risky it might be to reuse them. As you can see in the photos, there’s a definite wear pattern on each axle end and matching patterns on the cross shaft, but they don’t seem deeper than I recall seeing on others with under 100k miles. Also, one axle had kicked out and the snap ring was in the bottom of the diff, but there’s no visible damage in the area of the snap ring groove. The owner has no idea how/when this occurred so it may have happened before he bought the car in the late 70s.
So I have 2 questions:
1. Assuming the end play is 1/16” (.062) or better, would it be ok to keep using these axles and cross shaft if I make sure the axles and shaft go back in the way they were?
2. Should I be worried about the axle that had lost the snap ring, as long as there’s no visible damage to the axle?

BTW, I’m planning to replace all bearings and seals and I’m planning to adjust the side shims to tighten up the backlash which is currently at .016”.

I welcome any and all advice from @GTR1999 and any others who have been here before!

thanks
Bill




Cross shaft showing wear pattern from one axle.

Cross shaft showing wear pattern from the other axle.

 

Since it is apart, do it right and have a proper rebuild performed. This is no place to try and save some $$.

If that snap ring popped off once, it'll come off again and maybe get wedged in a gear this time.

Those stub axle ends are hardened, I don't recall to what depth, but once that area is worn, the wearing accelerates and next thing you know that 0.16" play is now 0.100..........

 

thoyer, Thanks for the advice! And good point about the snap ring maybe coming off again. I wonder if just replacing the stub axles and snap rings is enough to ensure it won't happen again, or should I replace the spider gears since the snap ring contacts them, as well?

 

Mine were in better shape than that and I replaced them. I couldn't imagine putting those parts back in with all the work it takes to get to them.

 

More then likely the clutch discs are worn which leads to the play in the stub axle. If it were my diff, I'd be doing a complete rebuild of the posi and getting it set up correctly.

There are a couple ways to go about doing it, rebuild using the factory style spring pack or eliminate the spring pack and dial it in with shims - lots of info on the forum on doing both.

If you decide to replace the clutches, avoid the "snowflake" type as they are prone to breaking.

I'd research how to do it and if you don't have the right tools or confidence to do it right, then send it out to be done by a reputable builder. This is not a unit you want to cut corners on.

 

The axle tips have wear, which usually doesn't show on C2 axles- if they are C2 axles. Chances are the diff was worked on before and possibly C3 axles used. You can check the bearings to see what brand they are, anything other than Hyatt or possibly NDH in 67, are replacements.
What is the distance from the tip to the snap rings?
Now, the quality of new and rebuilt axles today is suspect, and you need to know the differences among them.
I set axle endplay to 005-007" when building a diff. Up to 010 is ok over that I don't use.
The cross shaft is shot and new ones today are also suspect, so much so that I had my own made.

 

@GTR1999 Thanks for your reply, Gary.
The wear looks worse in the photos than it is. One axle measures .184” and the other .178” from the outer edge of the snap ring groove to the end of axle. The wear groove profile is only about .002 on one and .005 on the other.
Heat treatment coloring is visible on the splines from the grooves out. Is this a normal indication of factory process?
Any idea how deep the original hardening is?
If it’s normally something like .030 deep, is there someone who could grind the ends and do a Rockwell C on them to verify that hardness is OK?
Money isn’t the object here. I’m concerned, as you pointed out, that the parts available today may be actually worse than what we have.
You mentioned making your own pin… what hardness is required? I’d like to test whatever I buy.
And do you know what hardness is acceptable for the axle ends?

The bearings are NDH and the shims are original cast iron.

thanks
Bill

 

Bill
contact me directly and I will go over your options