Diferential off center??

[Hi-po SS 454]

On measuring for new wheels on rear, I find that correct back spacing measurement for each side on my 71 Chevelleis diferent by 3/4 inch. The passenger rear wheel is closer to outer wheel well lip than drivers side. Fitting a 10 inch wheel which is actually a total of 11 inch from tip to tip, the driver side is happy with 5.75 BS where the pass side is happy with 6.25. Was going to go with a happy medium of 6 inch back spacing on rear wheels.
Is this problem out of the ordinary??
Is there a problem in the suspension somewhere or no big deal???
Also I think I found my leaning problem. High on right rear and lower on left rear by and inch.
I can see the right rear spring has tight coils than and a 3 inch gap to next coil where the driver side has tight coils than a 2 inch gap to next coil, that can't be good.
Can I hear some thoughts on these problems please.

I want to replace rear springs BUT I don't want the ass end up in the clouds if I buy stock rear springs. Was thinking of going with 2" lower springs hoping they settle with wheel well lip just below the top of tire. Hope there some A-body guys out there.
ANY help will be appreciated.

[ProdigyCustoms]

If it has adjustable uppers they are just not adjusted correct. You can move the rear side to side quite a bit. If they are not adjustable, you have a problem

[Hi-po SS 454]

stock Non adjustable,

[buickfunnycar.com]

Not uncommon to see the rearends of these cars moved over to one side by as much as an inch...or more...but as Frank touched upon,you can get her back square again by loosening everything up and moving it to center.That should take care of your backspacing concerns...

If you're not happy with the ride height on stock coil springs,get yourself some lowered springs and see how it sits then.Make sure to put a good 300-500 miles on them to make sure you get it to settle a bit,if any.If after that,you're still not happy,time to trim a little bit off of each one until you get it where you want it.

Hope that helps you Rich.

[Hi-po SS 454]

Sure does John, I appreciate your help man....

[shep]

Also if one of the quarters has been replaced that can account for some of the difference.

[Hi-po SS 454]

Thanks man. The passenger side for sure has been changed, can tell by the seam in the trunk.
But the back space measurement from front axle flange to frame is larger on passenger side than drivers side. Like rear is farther over on pass side. Has been this way since I bought the car, just never measured till now that I want to change wheels.

[andrewb70]

If it has adjustable uppers they are just not adjusted correct. You can move the rear side to side quite a bit. If they are not adjustable, you have a problem

Frank,

Can you elaborate please?

Andrew

[JEFFTATE]

Also if one of the quarters has been replaced that can account for some of the difference.

Ditto .

Plus , check the centering of the rear axle relative to the frame.
Not the quarter panels.
Make sure the frame / suspension pickup points are square , etc...

[trig]

I was told by someone a long time ago that it is supposed to be offset to allow the bearings in the u-joints to rotate. If it is centered they will not rotate enough and cause the bearings to flatspot.

that is what i heard..............

[Hi-po SS 454]

Just pulled the rear springs and I find that the spring on the left is taller than the one on right and a little wider on the coils than the right on the upper area... left spring is 14 3/4 and right spring is 14 1/16. The left spring was from the pass. side of car which which was always higher than the drivers side. Now I know why the lean on the rear.
Problem now is to be lucky to pick the right spring for the ride height I want. I see where guys spend a lot of money and have numerous sets of springs, a hit and miss thing.
Also have heard compliants of buying say a 2" lowering spring and it ended up about the same height as the stock old springs. I just want the rear tire into the fender lip a couple of inches.
Any suggestions on spring size to use? (1" lower, 2" lower or??)

[DRJDVM's '69]

Yes its normal for alot of cars to have the differential offset to one side to help bearing rotation, but that just means the tube length from the differentail center to the axle flange is a different length..... so the pinion yoke isnt dead center between the axle flanges

In a perfect world the axle flange would be spaced the same on each side of the car..spaced from the frame and the quarter panel lip.... so the BS would be the same...with factory tolerances and damage/replacement parts over the 30 + years of the cars life, alot of stuff doesnt line up perfect anymore...

[andrewb70]

Rich,

Those springs are not original Chevelle springs. Late Chevelles springs had pigtails on both ends of the spring.

I actually have a set of H-O Racing rear springs that I am not using. You can see the ride height in the pictures, here:

http://www.popularhotrodding.com/fea...gto/index.html

PM me if you are interested.

Andrew

[chevella]

I had the same problem on my 70 chevelle. The car has the original sheet metal and had never been in an accident. Like you, I never noticed it until I started measuring for 17 x 11 wheels. Mine was 3/4 inch to the passenger's side. I bought a set of adjustable upper control arms and was able to center the rear up perfectly.


My car had the original rubber bushings and an open differential. The only thing I could attribute to the problem was, over time due to the majority of the power going to the passenger side wheel, the axel was being pulled to that side of the car and the rubber bushing developed a memory as they aged.

[Hi-po SS 454]

Rich,

Those springs are not original Chevelle springs. Late Chevelles springs had pigtails on both ends of the spring.
Andrew

WOW, didn't even realize that, thanks for mentioning that Andrew.
But why is that rubber boot the spring sits in, is made for a flat ended spring? Even has a stop for the very end of the spring to seat against.
Can't see a pig tail working with that boot I have. Unless the whole thing has been changed.
I'm lost now...
Not sure about your springs Andrew, can't tell for sure how the ride height would be on my car. I want that tire tucked a little more.

[Hi-po SS 454]

CHEVELLA, whos upper control arms are you using.
Your PM box is full can't PM you.

[chevella]

I am using Edlebrock uppers. Back when I got them they were about the best thing out. There are many more options now. When making your decision I would recommend getting some that use the Johnny Joint style ends.