Rear axle question.

Bassman/NZ

Bassman/NZ

Well-known member
Are all rear axles the same length? I'm referring to 37-48 car and pickup. I've assembled a rear end from a banjo, pinion and ring gear of unknown year but post 37, 47-48 bells, 47 pickup axles, brakes and drums (the axles had Made In Germany stickers on them). I lapped the drums to the tapers, and torqued them up to about 200lbs. However I'm scratching my head, as when I push hard on a back tire, I can hear a "clonk" which sounds as though it's coming from the area of the banjo, and I can see the drum move in relation to the backing plate.
I've tried different size washers on the axle ends, thinking maybe the nut was hard up against the key, but it made no difference.
I'm wondering if there may be a small difference in axle lengths that's causing this?
 
There's not a small difference that I know of, I think it's around an inch or a little less per side that the '42-'48 axles are longer than the '37-'41 axles. It's enough that you would know it and the drum would be that much short of covering the shoes.

There is axle end play between the a thrust surface on the inside end of the axle and the thrust surface on the spider cross. I don't remember what it is supposed to be, but I'm thinking no more than 0.005-0.010". It's enough that if everything is dry, you might here it, though. That could be what you're hearing as long as you got the differential carrier bearing preload set.

If it's only a few thousandths that you're seeing it move, then it could be just the end play of the axle as described above. If it is more than that, you may need to take it apart and check it out.

Good luck!
 
I have had Fords in the past that had the "clunk" in the rear axle sometimes when turning and it never caused any problem. In my opinion, I would not worry about it.
 
My right hand axle clunks like that, the left is ok.
It is play in the area of the diff gears.
I have not been worrying about it.

Should I be?
 
This movement is controlled by the play in the spider gears ,This may not bother you as they only operate when turning
 
When you swapped out your parts did you match the spider gears to the axle gears or just put a bunch of mismatched parts together? There are 11 tooth spider gears used on 39-48- 16 tooth axle and 12 tooth spider gears for the 35-38 - 18 tooth axle.
 
You must log in or register to reply here.
Back
Top