Rear axle mis-alignment?

[kustomkyle]

I always noticed that the rear of my 1986 Buick Regal Limited (307/200-4R/7.5 2.56 gear/base suspension/currently 110,000 miles driven daily rear round) seemed lop-sided to the drivers side and overall low in the rear. On certain parking lots, at a certain angle, the car almost looks like it has a completely flat tire or something in the left rear.

Just recently I decided to measure from the fender-well lip straight in to the edge of the tire. Doing this revealed that the passenger side is about 3-1/2 inches in and the left is about 4-1/4 in. I immediately thought that in order for it to be that far off something like a trailing arm must be bent. There is nothing visually wrong that I can see though. I asked someone who is far more knowledgeable about cars that me and was told it may just have bad bushings in the trailing arms. Or, possibly the rear springs are installed on the wrong side (some are side specific?). The rear springs were swapped a few years ago with ones out of a 50,000 mile 1984 Monte Carlo SS. Is this possible? Or does anyone have any other suggestions?

I do have all new springs on order (Moog 5608 front and 5379 rear), and plan on replacing the body bushings and bolts. I also have used (but now restored/painted) factory F-41 rear and front (1-1/4") sways bars ready to install with new Moog frame pad and end links. The plan is to have the car level front to rear and back to factory ride height and ride (if not slightly higher and smoother). Right now the car just feels un-sorted and bumps in the road reverberate throughout the body. The front suspension has no aparent visual issues in that the wear indicators on the ball joints are where they are supposed to be, tie rods are tight, etc. (but all are likely original). I did have to replace the center link about 3-4 years ago, other than that the shocks are about 2-3 year old in the front (Monroe Sensa-Trac) and rears approx. 5 years old (regular gas Monroe, blue)

 

[Pontiac455]

If the bumps reverberate thru the whole car i would check the bodymounts amke sure the body isnt laying on the frame. If ya wanna check the rear springs crawl under the car with a measureing tape and measure the height of each spring with the sprung weight. Both sides should be close unless ya have a keg of beer in the rear pass side. lol

 

[565bbchevy]

I would first visualy check the rear springs for a broken coil this can happen with age and miles. Highly unlikely that you have a broken trailing arm but bushings they could be completely worn out and body mounts could be broken /missing another common problem.
Now also in extreme cases I have seen the frame split behind the rear tires ( typically from rust) causing that side to drop and sag but can be repaired with different frame rails or welding plates to reinforce your existing rail.

 

[kustomkyle]

Frame rails were actually replaced at approx. 85,000 miles in May 2009. The car was from Williamsport, PA, and the rails had rot, and eventually the left cracked behind the wheel. Never had anything relating to that causing sag though. When the rails were replaced, everything was measured and set correctly if not better than when is was new, and we even set a 5/8" gap on each side between the frame and the inner wheelhouse. New body bushings and bolts in that area, just never got around to doing the rest yet. Amazingly, despite the frame rot the trunk floor was clean, just had to repaint it.

So whatever it is, it has to be in the suspension. Springs are not cracked. Maybe these cars were offset from the factory?

 

[565bbchevy]

Then I would replace the rear springs first and they are not side specific unless it is a drag race spring set up.
If you get a chance post a few pictures (suspension,frame,control arms,springs etc.)

 

[-83MONTESS-]

Any photos? Im pretty sure most gbodys came with offset rear ends. Im not sure if the engineers planned for it to be off to one side or if its just a wear thing. Every Gbody I see seems like the rear is sticking over to one side more than the other including mine. My old rear tires would only rub the frame on the drivers side because the passenger side stuck outward more.

 

[565bbchevy]

Any photos? Im pretty sure most gbodys came with offset rear ends. Im not sure if the engineers planned for it to be off to one side or if its just a wear thing. Every Gbody I see seems like the rear is sticking over to one side more than the other including mine. My old rear tires would only rub the frame on the drivers side because the passenger side stuck outward more.

I believe he is referring to ride height with one side being an inch lower than the other, not the width of the rear end in relationship to the frame, but you are correct on that point.

 

[pontiacgp]

the springs tend to settle on the driver's side first cause of our fat a$$ses, at least in my case it did. Moog springs aren't expensive. The side to side issue I resolved with putting the body on the frame straight.

http://jeffd.50megs.com/Moog_Spring_Page.htm

 

[kustomkyle]

Any photos? Im pretty sure most gbodys came with offset rear ends. Im not sure if the engineers planned for it to be off to one side or if its just a wear thing. Every Gbody I see seems like the rear is sticking over to one side more than the other including mine. My old rear tires would only rub the frame on the drivers side because the passenger side stuck outward more.

I believe he is referring to ride height with one side being an inch lower than the other, not the width of the rear end in relationship to the frame, but you are correct on that point.

Actually, the car is both off-centered and lop-sided. So maybe the off-centering can be fixed during the body mount bushing replacement. I would do it sooner than later but only have a small jack and a gravel driveway. Thanks for all the quick responses.