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here are some pics of the two u bolts side by side, etc...

mine is on the right in the side by side pics. and on the top in the stacked pics.

if mine is bigger it is only slightly bigger. it is more evident when they are stacked.

it doesn't seem like they would make that much difference though, but i know that if i tighten the nut any more i will be afraid it will bust off and i don't want that!

the spacer also seems to me to be longer than the one you stated in your PM, HH56.

i don't know what could be the issue, i am confused. i put everthing together right, even triple checked.

put the bushings under the rear end with the spacer piece installed inside them and put the u bolt through, put the bottom plate on and tightened the nuts and that should be it...that is all i did on the other side. i also tested my tightening torque side to side and they are roughly the same, so any more and i wouldn't feel comfortable. the bushings seem to be squishing the same amount as well.

hmmmmmm.....

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i also don't understand how i couldn't get mine on, but i was able to get the new one on fine....especially if min is longer....maybe i wasn't trying hard enough or something. i hate brain ticklers like this.....

I agree, there's not enough thread I'd be comfortable with either & obviously a difference. As I said that bolt was from a 55 axle which had been installed on a 56.

Would explain different part #s between 55-6 though. They changed something & made the 56 1/4" thinner. Those spacers are 2 3/8 exactly and yours appear 2 5/8. Without side to side comparison of pieces don't know what. Maybe someone on site does. Believe it was Craig mentioning problems he had with shock mount breaking but don't remember year or details.

Options I see are:

Continue looking for the proper 55 bolt. So far, that hasn't seemed to work.

Take your old damaged bolt and see if your dad or uncle could cut them both & weld a 1/4 piece on each side of the new one so it would be under the spacer.

See if any possibility a 2 3/8 spacer would work. If it would, then there is another bolt so they'd match.

Did I miss anything anyone?

who would have thought there was so many changes in between all the years. crazy world!

the camera is casting a shadow on the spacer and it is actually 2 9/16ths roughly. i don't know why there is a difference between the right and left side. maybe there are different size spacers on my passenger's side, i will take it back apart too and see if the spacer is the same and see if the u bolt is the same too. i am pretty sure they are from memory, but i will check to make sure.

i just hate it cause all this doing and undoing is scratching up the paint a bit....;0( oh well....its gonna happen when i drive it i am sure.

thanks for the help and i will report my findings tomorrow.

later dude,

Hank

Just a couple of general comments. Those U-bolts are not exactly precision pieces, and just a slight difference in the shape, radius of the bend, thickness of the flat part etc. could throw things a few eighths off when tightening them to a round, cast surface. I would bet it's a combination of the things that HH mentioned.

Quote:

In a situation like this, a torque wrench might not tell you the whole truth. You could have all kinds of binding between the U-bolt and the axle housing on one side, and little or none on the other.

Tightening each side in gradual, even increments may give a different result than tightening--or even snugging up--one side first and then the other. When all else fails, one last thing to try... swap sides with 'em.

My and probably worth twice that in today's market.

i did notice that the one that HH sent was alittle more peaked at the top, more like a triangle style and mine is more round and curvasious at that top. it also look from the paint indentions that the one HH sent is grabbing on the sides of the u bolt. i wonder how many of these bolts the factory workers had to go through on each car to get the right one to fit. must have been a PITA!

i will take apart the other side and see what i can tell when comparing it.

we'll get it straightened out, we have come to far to give up now ;0)

Later dudes,

Hank

I remember and admire your reasons posted earlier for wanting OEM ones, but I still think you're better off making new ones, in my thinking its too important a part to depend on possibly fatiqued old parts. BTW, the 55 rear axles were Packard-made and the 56's were Dana, are the tubes identical in diameter?

tubes?

Tubes, the round part of the rear end that encloses the axles, extensions of the carrier that extend to the backing plates. In many differentials (I believe the 56 Packard/Dana is this way) they are actually separate tubes welded into the center. Much less expensive to manufacture I suppose than the entire assembly being one huge piece.

O-D brings up some good points and re tube diameter, I hadn't thought about that but I'd wager they are fairly close. Will try and look at the 56 tomorrow & take a few measurements just more out of curiosity now.

Since bolts were on the 55 axle & installed on my 56 when acquired, they had to fit. There has got to be a difference lower down in the torque arm or shock mount because that is where those smaller spacers fit.