Ever since I've owned my car the rearend has been further to one side than the other, making one tire stick out more and occasionally rub.

Is there an easy way to fix this?

I have adjustable upper control arms if that helps.

mine also did this before i took off/ refit body i think its factory fit. But i think its better now i refit body, going back 2 when i was younger i had a 58 bel air that had that bad top wishbone top arm setup on it, it broke one night after some abuse so i put a 9 inch in it with 4 arm set up home made like our A bodys , but also made up a adjustable pan hard rod setup for it, using bushes similar to front bottom control arm bushes [A/body] it made car handle a hell of a lot better. might be worth a think

Mine is off also, I was thinking of going with adjustable upper control arms and seeing if I could center it that way, In theory it works. (in my head :D)

LK

Yes, adjustable uppers allow you to center it. If you need to move it too much, you will also need adjustable lowers for it to track straight.

One must ask----is the differential centered on the frame????

Same question about the differential being centered, my 67 is off a little but the diff looks centered. I'll try the upper control adjustment but that seems to affect the pinion angle only?

I have the same problem, and really noticd it when I was trying to stuff the biggest wheels and tires in rear. I asked UMI about there Adj. uppers, if using them to center the rear is advisable. There answer is NOT ADVISEABLE.
I have UMI adj uppers.
I use a 1/4 inch wheel spacer on one side of car.
Yet I have heard a few guys that center the rear with adj uppers and have no peoblems.

since the uppers locate the rear, they can be used to center it. its usually a combo of the body being slightly off, coupled with the uca issues. if youre off a bunch, start looking for the issue thats causing it.

I used adjustable upper AND lower control arms to center the 12 bolt rearend under my '70.
We did it on an alignment machine with live readings to be sure it would also track correctly.
Works fine. :thumbsup:

I used adjustable upper AND lower control arms to center the 12 bolt rearend under my '70.
We did it on an alignment machine with live readings to be sure it would also track correctly.
Works fine. :thumbsup:
Bill did you have this done at your local alignment shop or frame shop? thanks

Bill did you have this done at your local alignment shop or frame shop? thanks

My bro-in-law and I did it on his Hunter windows based, lazer driven alignment machine...it was easy. :thumbsup:

http://a24.ac-images.myspacecdn.com/images01/98/l_054eeeff2e32ba6b026664c086f98da7.jpg

Centered rear end --- CHECK

I'm just confused, seems like messing with the control arms would only roll the rear not move it side to side...

maybe I just shouldn't worry about it, just a pet peeve, every chevelle I've seen seems to be this way to some extent

I'm just confused, seems like messing with the control arms would only roll the rear not move it side to side...

maybe I just shouldn't worry about it, just a pet peeve, every chevelle I've seen seems to be this way to some extent

Me too.
Seems like it would make the springs lean. :confused:

the ucas are angled out thus making them the centering device on a C4L. therefore, lengthening one while shortening the other will move the rear side to side. you cant twist your rear, so it only moves them side to side, unless you shorten or lengthen both.

that pan hard rod setup on tuned by tad is the way to go if you are serious car will handle a lot better to

or this unfinished piece........ it still needs a lot of work.

http://www.fquick.com/images/vehicles/full/23712221839.jpg?1230517792

Say for example your axle needs to move RIGHT...

Lengthening the left upper will move the axle right, and point the pinion up slightly. Shortening the right will move the axle right, and point the pinion down slightly.
A combination of both will move the axle right, and keep the pinion at the same angle.

Because the lower arms are not parallel, moving the axle right will move the right tire forward very slightly, and the left tire back, so small adjustments on the length of the lower arms would be required to make it track straight if you use the upper arms to move the axle laterally.

Seems like it would make the springs lean. :confused:A small misalignment of the springs is no big deal... they flex, that's their nature. ;)

My new Moser is not centered, it's off to the passnger side exactly 1/2" .

The body is on straight. And really, there's not much room for movement, as the floor bracing is about 1/8" from the frame on the sides.

I have adjustible uca, but non ad lca.

It still seems to me that making one ca shorter then the other would make the rear end non square in the car.

Mine sticks towards the pass side too. As does my dads 69 chevelle...and 90% of the chevelles I've ever seen. Its weird.

It still seems to me that making one ca shorter then the other would make the rear end non square in the car.

you are correct, but not becasue of the uppers, but now the lowers. when you move the rear over, you alter the angle of the lowers on a horizontal plane. one has a greater angle, on less of an angle. that changes their effective length and therefore makes the rear no longer square. so like derek said, you have to square it back up with the lowers.

chances are though that something is wrong if the rear is perfectly centered and not square. its more likely that the uppers are out of adjustment.

btw, running real quick numbers, shifting the rear over 1/2" only shortened one lca .016" and lengthened the other by the same. that would be a 1/32" difference. i dont think you would EVER notice any dog walking with that.

you are correct, but not becasue of the uppers, but now the lowers. when you move the rear over, you alter the angle of the lowers on a horizontal plane. one has a greater angle, on less of an angle. that changes their effective length and therefore makes the rear no longer square. so like derek said, you have to square it back up with the lowers.

chances are though that something is wrong if the rear is perfectly centered and not square. its more likely that the uppers are out of adjustment.

btw, running real quick numbers, shifting the rear over 1/2" only shortened one lca .016" and lengthened the other by the same. that would be a 1/32" difference. i dont think you would EVER notice any dog walking with that.


Since I don't have adj. lowers, moving the uca to move it wont work then?

Actually, since the rear end is 1/2" more to one side, I'd only need to move it over 1/4" to make the rear center in relation to the wheelwells.

Check out this image, it's a top view of our upper StrongArm. When I was installing our stuff on my 70 I noticed that the tube was welded slightly offset about a 1/4" to the right. So, I assumed that the other side was welded offset to the left, but it was exactly the same. So, I assumed that I got one driver side arm and one passenger side arm......wrong again. I called Rodney up (head fabricator) and asked him about it. He said this is how the factory arms were built, he just duplicated it. The axle centers up perfectly on all the cars that we have done. I'm not sure if all manufacturers do the same....but I could see that causing problems.

http://www.chevelles.com/forums/attachment.php?attachmentid=20361&stc=1&d=1239719628

http://c1.ac-images.myspacecdn.com/images02/50/l_a718ced20fcd4146818264689ab44614.jpg

track width widened a whole bunch.
Rubbing = zero

Check out this image, it's a top view of our upper StrongArm. When I was installing our stuff on my 70 I noticed that the tube was welded slightly offset about a 1/4" to the right. So, I assumed that the other side was welded offset to the left, but it was exactly the same. So, I assumed that I got one driver side arm and one passenger side arm......wrong again. I called Rodney up (head fabricator) and asked him about it. He said this is how the factory arms were built, he just duplicated it. The axle centers up perfectly on all the cars that we have done. I'm not sure if all manufacturers do the same....but I could see that causing problems.

http://www.chevelles.com/forums/attachment.php?attachmentid=20361&stc=1&d=1239719628

I'm using these, they're not offset.

http://static.summitracing.com/global/images/prod/large/edl-5249.jpg

I have had the same upper arms since 2004.
Even with full edelbrock 4 linck new bushings and sway bar on Nitto 555 295/18s,
fully aglined on a hunter 600 by me. Our Elco was still retarded.

To be honest all the factory tolerences are way loose.
Our ElCo Rosie would always track to the right with !any! throttle or power application.
Even at normal freeway merge speeds.
WOT from a stop it would want to turn right hard some times and wheel hop staright others.

When I took the diff out and measured everything,
nothing was straight nothing was symetrical.
All the mounting holes were round against my driving impressions.

It took a ton of work to get the 67' ElCo even close to square.

To be honest I stumbled into the miricle of the pan hard rods with my Impala
The car woud tail whip violently coming out of corners as the frame re centered with the suspension and axle.
a pan hard was put on as a guess to control the exit speed tail whip.
I learned a whole lot since then ...2003

Now on the Elco you cant even get a your whole pinkly between the rear fenders and the 295s!
I have room to widen the rims a 1+" on the inside!!!
Maybe next year...

thanks for the info guys, I might try adjusting my uppers until i can afford to do a panhard bar

you may want to test this.

Go to the rear quater.
Face the fender and push it in time..
enducing tail wag.

Can you hear the C-clips clicking, do the bushings squeak,
Let it talk to you!

http://c1.ac-images.myspacecdn.com/images02/50/l_a718ced20fcd4146818264689ab44614.jpg

track width widened a whole bunch.
Rubbing = zero

Tad-
Is the Panhard mounted to the brake caliper? If not, what's that outboard mount look like?

Tad-
Is the Panhard mounted to the brake caliper? If not, what's that outboard mount look like?

Scotch,
This is panhard 2.0 for this car.
Major design upgrades were included this round.
It looks like its attached to the brake caliper cause...
I used ALL avaliable lateral area to get the longest PHB under the car as possible.
this reduces axle shift vs suspension travel

A cross bar from frame to frame was a major improvement over ElCo PHR1.0 and Impala PHR 1.0
The basic panhard concept looks like this:
http://c2.ac-images.myspacecdn.com/images02/68/l_213543ceafac4e7ca53c2ffe9d0674e1.jpg

the live side of the PHR Ihad to clear the coil overs, and the brakes but be almost in the wheel.
So the bracket material had to be stout and double shear
axle mount on the far side looks like this:
http://c4.ac-images.myspacecdn.com/images02/83/l_6e61d7e9f18c4f38a37a42bc12c1983f.jpg

this is the axle PHR attachment point with shocks and brakes
parking brake cables are missing in this picture
the buisness is very straight I could jack the car up and drop it w/o popping the painters tape holding in the rod end bungs :-)
http://c4.ac-images.myspacecdn.com/images02/96/l_a4e8687d9ece40f9ac1b2af6a6a1e707.jpg

-would I do this mod again?
HELL YES!

-would I change anything?
I might go with a late model 94-96 B-body rear end and have custom axles made with 5x4.75 pattern and use a Torsen T2 differential.
That would make the brake swap go quicker and lower the total investment and get a better diff out of the deal.

Since I don't have adj. lowers, moving the uca to move it wont work then?

i think it would work. my quick math showed one control arm only being longer by 1/32 of an inch (its not perfect since i didnt account for their horizontal starting angle, but its close). i dont think you could get much closer in length if you tried. i have adjustable lowers and i know getting to .030 is pretty tough. but, it would get my stamp of approval.

Tim

Scotch,
This is panhard 2.0 for this car.
Major design upgrades were included this round.
It looks like its attached to the brake caliper cause...
I used ALL avaliable lateral area to get the longest PHB under the car as possible.
this reduces axle shift vs suspension travel

-would I do this mod again?
HELL YES!

-would I change anything?
I might go with a late model 94-96 B-body rear end and have custom axles made with 5x4.75 pattern and use a Torsen T2 differential.
That would make the brake swap go quicker and lower the total investment and get a better diff out of the deal.


Okay...well, make one for my Ford 9-inch then. Killer setup Tad.

Okay...well, make one for my Ford 9-inch then. Killer setup Tad.

thanks :-)

I tried moving my rear end to the side just by moving the uppers. It also move the rear end front to back. I'm not sure if it would of made a difference, but I wasn't comfortable with it.

So for now, I'm just going to keep it as is.

Mine is actually shifted toward the drivers side. I have 7.5", from axle to quarter on the drivers side, and 8" axle to quarter on the pass.

I tried moving my rear end to the side just by moving the uppers. It also move the rear end front to back. I'm not sure if it would of made a difference, but I wasn't comfortable with it.

So for now, I'm just going to keep it as is.

Mine is actually shifted toward the drivers side. I have 7.5", from axle to quarter on the drivers side, and 8" axle to quarter on the pass.

After another attempt, and some more measureing I got the rear end centered by moving one upper control arm.

I could only measure one side or the rear end moved back about 1/16" further then the other, measured at the axle.

Anyone know if that'll be a problem?

It works I adjusted my upper control arms in and out and got the rearend in my 69 Chevelle dead center , but mine was only off by about 1/4 inch. I measured from the inner side wall of my tires to the frame rails. Eye balling and measuring the body on mine it sits on the frame straight, equal distances on both sides.
Do you guys know how much tire clearance you have on the inside ?????
Right now I have about 3/8s of an inch sidewall to frame. Is there much laterial movement between the body/frame and the rearend ?
Gene

Great Post..

I just found out that my rear is offset to the passenger side about 1/2".

If getting it to move over with the UCA's seems to work I will try that first.

From what I read, I need to Shorten the Left Upper.

well I finally decided to try this (I know, its been a while)...shortened the driver side and lengthened the pass side and the rear is now center

it did strike me as odd just how much I had to move each of them to get it done though, maybe because my arms aren't offset like the ones pictured in the thread

the driver side is so short its about out of adjustment actually

I have related question for you guys...

I just upgraded to C3 rear adjustable UCAs and I was also surprised how much I had to adjust to get it centered. I don't have the Johnny joints on the UCAs yet but that's next on the list. For now i'm running a rubber bushing on the housing and a poly on the frame side of the UCA.

The OEM was off by about 1/2" from center (I moved it 1/4" towards the passenger side) as many have already mentioned.

So here's my long winded question...I'm running 10" wheels in the back and i'd really like to maximize my tire back there. With the offset I have on the wheels I have only about 1/4" inch from the fender when measuring the clearance between the wheel/tire and inner side of the fender. I know there will be some side-to-side movement of the rear during hard cornering because i'm not planning to run a PH or a Watts. I'm wondering what you folks think is a good and safe allowance to allow for side to side movement so that I don't tear up my tire when doing a hard turn?

I'm about to go in for new tires and I can go for anything in between 265 to maybe 305. Was leaning towards a 295.

Before jacking the rearend around, check the centring of the reaarend to the frame versus rearend to the body. That will tell you whether the body is bolted down off centre or if the rearend is off centre in the chassis. If all the arms and bushings are in good condition, I'm betting that most of the time, it is the body that is off centre.

Before jacking the rearend around, check the centring of the reaarend to the frame versus rearend to the body. That will tell you whether the body is bolted down off centre or if the rearend is off centre in the chassis. If all the arms and bushings are in good condition, I'm betting that most of the time, it is the body that is off centre.
previously done and done :)

car is on poly body bushings

anyone have any real-world experience with rear end side-to-side play with modern UCAs & LCAs?

I really don't want to tear up a good set of tires but want to maximize tread width back there.