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Discussion Starter · #1 ·
I've been doing measurements for the new rim/tire combo and I've realized that my right tire sticks out 1/2 inch more than the left side. I'm guessing the axle is not centered. Looking under the car and through my shop manual, it seems that if I support the rear on it's frame that I could un-do the U-bolts and shift the rear axle over just slightly but I'm really guessing that this is much easier said than done. A shop has replaced the leaf springs some time in the past, so maybe they didn't get it alighned just right?

But I'm wondering if this non-centering could cause vibrations? I have some funny vibrations, but I kind of deal with it- but if this could be a knowing problem, maybe I could fix it.

If having the axle's slightly off-center (which from researching was somewhat common from the factory) isn't a problem I suppose I may just use a spacer on one side to have the tires fit equally.

If I can't do it and should take it get fixed, what is a shop going to charge me?

Chaz
 

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My car is up on stands right now for the same reason. I've removed the u-bolts (for painting, while I'm at it) and moved the housing. It's easy. Try it and see if your vibration goes away.
 

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are your shackles perfectly vertical?

you could have:

worn out shackles
broken leaf spring centering pin
bad leaf spring bushings
 

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Discussion Starter · #4 ·
Hmm... I did look at the shackles but did not note whether they were perfectly vertical. I guess we'll see what I come up with...

Chaz
 

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I just noticed a different problem, my passenger side wheel doesn't look centered in the wheel well. When I dis the floors and subframe connector.
I leveled measured and squared all the suspension points and they're all good. But sure enough the right rear tire is slightly biased toward the rear of the car.

Anyone ever see that? I know the car was hit at some point in that corner, could the sheetmetal be off?

I was saving this for a new thread but it seemed to relate.

Andy
 

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could be leaf spring centering pin sheared off

i would think if the sheetmetal (subframe) was out enough for you to see it in the tire, you would have some body panel alignment issues
 

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The subframes are O.K., and the subframe connectors also pick up that hole and reinforce it. Nothing showed up at alignment either so I'm thinking a misalligned panel.

Andy
 

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While installing the lowering blocks on mine last weekend I notice there is some play where the axle meets the leaf. At least 1/4" each way. I was able to slide mine over 1/4" and center it almost perfect.
 

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i had the same problem.

i fixed it by replacing my old leaf springs and mounts, shackles, etc. after I bolted everything back in, the rear end was centered perfectly...

max
 

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on my '68 the driver side rear wheel is about 3/8" forward in the fender opening.
The door gaps are slightly wider on the driver side (about 1/32" each) than
the passenger side. Carefull measuring on the underside shows that the frame
structure is about 1/4" short on the driver side.
These cars were spotwelded from many pieces with a lot of tolerance/assembly build up.
IMO this variation/problem wasn't unusual.
 

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it seems that if I support the rear on it's frame that I could un-do the U-bolts and shift the rear axle over just slightly but I'm really guessing that this is much easier said than done.
You're right.... much easier said than done.

You've forgotten that the leaf springs have an alignment bolt holding the spring pack together. The head (or nut) of this bolt on the underside of the spring pack fits into the "centering" hole on the spring perch. Although the spring perch centering hole is bigger than the spring pack bolt head, I can't envision you gaining more than a 1/16" from this method.

You could cut your spring perches off and re-center them.....? But this would be a LOT of work and I do not recommend this.

The easiest solution to your problem is to either ignore it or install a spacer/adapter under the "shorter" wheel.

Dave
 

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I didn't gain my fudge factor from the perch plate, I gained it from the mounts on the axle housing. There is plenty of wiggle room on mine. Loosen u-bolts, move rear end where you want it, retighten.
Glad I'm not the only one with this issue. I felt much better when I found out how much play I had after u-bolts were loose.
 

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So you loosened the two U-bolts (on each side), pulled the rear-end over (an amount to center it) and then re-tightened the U-bolts?

Dave
 

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The pin on my leaf was about 3/8" dia and 3/8" tall. The hole on the bottom of the axle flange is a tappered hole starting about an 1" dia tappering to 1/2" and about 1/2 deep. Now you can see where the play comes in at. I'm shaving a 1/4" off my blocks Sat to raise the rear 1/4" hoping this will help my scraping alittle. The hole in the block of almost 5/8" deep.
 

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Dave, I don't understand this either! Seems to me you're right. The leaf spring
bolt centers the housing within the hole of the plate and the housing bracket.
Only the hole to bolt clearance adjustment would be availible.
 

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Discussion Starter · #17 ·
Yes Dave, I did notice the centering bolt when I looked under there and that is the part that makes me worried that *I* won't be able to do this task very easily. I had wondered if maybe this could cause any obscure vibrations cause then it would also be mandatory for me to fix.

I have a question about the centering bolt... how far does the bolt stick out? It seems mine is sheered right where the nut tights up on the leafspring. Matter of fact, it doesn't even look like I could get a socket on the nut...

There very well may just be more to it for me than a non-centered axle, such as frame alingnment *shrug*

Chaz
 

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Mine is off slightly too. It is hard to see by eye but one of my tires will rub lightly sometimes. The other one never does. I am upgrading the rear springs soon so I plan to address it then.
 

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how far does the bolt stick out? It seems mine is sheered right where the nut tights up on the leafspring. Matter of fact, it doesn't even look like I could get a socket on the nut...
Not much. Usually, there is only 1 or 2 bolt threads protruding through the nut. However, if you have NO threads protruding and your nut is "worn".... this may be a clue to something amiss. I doubt it would recapture the .25 inch that you need to re-center your rearend, but it may clear up some other things, like vibration...

Check both sides.

Are they both worn like this?

If they're both worn, that indicates (to me) that at some time in the past, the rearend has been operating "loose" on the spring packs. How loose? Who knows... but loose enough to grind down the nuts.

Has any elongation of the alignment holes on the spring perches occured? If so, weld 'em closed and re-drill 'em.

If you're re-using your original spring packs, remove/cut off the existing bolts and install some replacements.

This should get you where you need to be. If you still have the "rearend off center" problem. You've cheaply eliminated one variable/possibility.

After you've driven 100 miles (or so), it is important that you go back and re-torque the spring pack U-bolts.

Dave
 
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