Bent diff housings

fordscript

fordscript

Senior Member
Some time back, there was a discussion on putting new sleeves on worn bearing surfaces of pre-48 diffs. Someone said that they always checked the diff housings for being straight, and that they were nearly always bent. I have just had 2 housings re-sleeved, and on checking them for being straight, have found they are both 15 thou out. Any thoughts on whether this is acceptable, and if not, where to bend them. The machinist suggested taking the .015 off the gasket surface...didn't sound like a good idea to me! Thanks, Gordon
 
The most common method of straightening is spot heat and then hit with water. You do this with the indicator on it so you know how far to go.
You will need a GOOD center cut on the outer end and a center to ride in the bell end to support the housing in the lathe properly.
 
When I first heard about bent axle housings, I asked two well-known early Ford machinists about it. One said he'd never seen a bent one. The other said most of them are bent. As Pete implies, its not all that easy to properly chuck these things up and check the bearing surface. I'm wondering how did you determine yours was bent? I'm asking because I've got two I need to check before sleeving.
 
I am a HAMB guy so I know about welding warping axles. I developed a test to see if the axle housings are bent and if straight after correction. You have to assemble the whole thing with wheels also. I put some greased sheetmetal under one wheel and chock both wheels. Put a dial indicator on top side of the tire without grease and turn the whole housing over and over. If the housing is bent, you will see movement.
 
Andy's method will work fine.
I always check the housing before sleeving the outer bearing area.
While I have it in the lathe I cut a center in the outer end. This puts
the old bearing surface concentric to the new center which will be used to grind the bearing area in the crank grinder. I have a fixture that bolts to the bell end and centers on the carrier bearing surface.
The wheel bearing surface is ground and the sleeve (made in house) is subsequently installed..The housing is put back in the lathe and straightened.
The housing is then put back in the crank grinder and the new sleeve is ground to size.
Not as quick as the way some do it but I have NEVER had one I repaired fail and some have run at Bonneville.
 
The way I hold these things in the lathe is to remove the inner bearing cup from the housing, and machine down a suitably sized piece of material, held in the 4 jaw, to the same dia as the bearing cup. This ensures dead concentricity. Then, using the tailstock, I 'press' the housing onto this stubshaft. Use a suitable centre or pipecentre to support the outer end. I can now spin the assembly to machine down for the sleeve, also check the flange that bolts to the banjo. In my experience, at the very least I've had to just take a slight cut off of that face to true up, other times the housing needs some straightening beforehand, however, that face should be restored at the same time as the outer end is repaired. Brian
 
So your "stubshaft" is pressed into bore for the differential carrier bearing and then extends all the way through the housing to form a center on the other (outside) end. Is that right? Maybe I'll try to have one made like that. Thanks. John R.
 
Have any of you ever known anyone who had some kind of failure from a slight bent axle housing? I never have. Just wondering.
 
John R, No, the stub shaft merely 'duplicates' the carrier bearing, the outer end is supported by a centre or pipecentre in the tailstock of the lathe. The thing is to ma chine the stub from new each time because then it is running dead true; also, you'll need to remove the housing, complete with pressed in stub shaft, from the chuck in order to be able to knock it out. I am about to do another coupla housings, so will take photos as I go and try to post them on here.
Jerry, running with a bent housing results in abnormal wear in the spider gears and gear on end of axle, and inside of the carrier. Brian
 
Thanks Brian, maybe I'm getting the picture now. Photos will help. It seems to me that if you use the tailstock and center it on the ID of the housing's bearing snout, it would be next to impossible to see if the snout is out of alignment with the carrier bearing. Maybe I'm making it more complicated than it really is.
 
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