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Narrowing a 9" ford rear end

13K views 6 replies 6 participants last post by  S10xGN 
#1 ·
I am narrowing a 9" ford housing in my shop to go under the Imperial. I borrowed a narrowing jig. I have never done this particular activity before but I won't let that stop me .The jig came with no instructions.

My question is, what is the tolerance for misalignment of the bearing bore in the housing end, both radial and axial. I looked all over the 'net and found nothing other than a few people saying that if you could get the axles in and the wheels rolled, then it was OK. :confused: I know it should be a little closer than that.. (I also know the tolerance isn't 0.00",so it must be something)

Also, I am working with a rear end housing with the old style big,(3.150" OD), bearings and the heavy axle tubes. (1/4" wall)
The size of the housing end requires the end of the axle tube to be counterbored to allow the housing end to be inserted. I guess this isn't a problem with the thinner wall thickness tubes.

Has anyone here had any experience with doing this. The od of the housing end is 2.665 and the ID of the tube is 2.55 or so. It is a seamed tube so it is out of round as well as not concentric with the alignment jig bar. I have a feeling that I am going to be hogging it out to fit with a die grinder to fit but I thought I'd ask here and see if anyone had another suggestion.

The one rear end shop around here that does that service told me they cut the insert end off, and just buttweld the end back on when they narrow them. I guess he doesn't realize that is where the seal is supposed to seat. I'm glad I am not taking it there.

Thanks for reading this, Mikey
 
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#2 ·
When i've done it, I shot for .015 max and found that even stock was off that far. I just cut the tube, hacked off what I didn't want, and welded it back together. I did machine the inside/outside and so there was a slip fit. Those bearing are pretty conforming.

Can you cut he tueb from the bell and shrten it there. I've changed axle tubes that were bent in craashes that way. Beware of the plug weld if any.
 
#3 ·
Thanks, johnsongrass. I already welded the four bar brackets on the tubes so cutting it at the center section would be the hard way at this point.
I called moser and found that the new ends they sell are longer (so they accomodate the seals without going into the axletube), and are designed to be buttwelded to the tubes. I guess if everyone else is doing it I can too. I'll just cut the insert end off and run a bearing with an OD seal.

The tech guy had no tolerance dimension for misalignment. I will shoot for the .015" you suggest. It sounds right to me :)

later, mikey
 
#4 ·
The housing will warp a little from welding on the brackets so I always weld on all brackets before welding on housing ends. Set up the fixture and tack the ends in a few places then go back and weld them on. If you can spin the alignment bar with your hand you will be ok.
Bob
 
#5 ·
Keyword - "bind"

The keyword is BIND. If, when you get all tacked together ther's ANY bind in the bearings, you need to go back to ground zero! If it feels like there's a 'snag' in the movement think about hiow you're tack welding it and do it again, untill there's no bind in the axle or carrier bearings.







powerrodsmike said:
I am narrowing a 9" ford housing in my shop to go under the Imperial. I borrowed a narrowing jig. I have never done this particular activity before but I won't let that stop me .The jig came with no instructions.

My question is, what is the tolerance for misalignment of the bearing bore in the housing end, both radial and axial. I looked all over the 'net and found nothing other than a few people saying that if you could get the axles in and the wheels rolled, then it was OK. :confused: I know it should be a little closer than that.. (I also know the tolerance isn't 0.00",so it must be something)

Also, I am working with a rear end housing with the old style big,(3.150" OD), bearings and the heavy axle tubes. (1/4" wall)
The size of the housing end requires the end of the axle tube to be counterbored to allow the housing end to be inserted. I guess this isn't a problem with the thinner wall thickness tubes.

Has anyone here had any experience with doing this. The od of the housing end is 2.665 and the ID of the tube is 2.55 or so. It is a seamed tube so it is out of round as well as not concentric with the alignment jig bar. I have a feeling that I am going to be hogging it out to fit with a die grinder to fit but I thought I'd ask here and see if anyone had another suggestion.

The one rear end shop around here that does that service told me they cut the insert end off, and just buttweld the end back on when they narrow them. I guess he doesn't realize that is where the seal is supposed to seat. I'm glad I am not taking it there.

Thanks for reading this, Mikey
 
#7 ·
I did one years ago using just a piece of 3" x 3" angle iron and "C" clamps to jig up the tubes and there was no binding at all. Can't even imagine what the tolerances on that job were!

Russ
 
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