rear leveling - frame issue?

[vettebuff]

On my '86 the rear left side is about 1" lower than the right side. On front it is about 1/2" lower on left side. It can be leveled by adjusting the screws at the rear springs, but need 2-3" different setting left-to-right. The rear spring has been taken down and turned and all links have been disconnected and greased, front and rear. No visible damage to front spring or other suspension parts. Still not level. Can this be a frame issue?

Background: after owing the car for 20 years I spin off the road and slid sideways (left side) on the roadside, plowing both front and rear left wheels in the dirt and finally hit the 6ft high shoulder with bumper at front left side. The front "bumper" and the frontmost frame cross member was damaged and replaced. The shop said that the front portion of the frame at the point where the bumper is attached also was bent but not more that they could mount the new bumper with some adjustment shims. (However, I doubt that that shop has the right knowledge, so I have my suspicions). The doors close and open exactly as before, and with same gaps.

To me it was not that of a hard crash so I have difficult to see the frame being affected as far back as the point of the front suspension. Now I am living on last piece of hope, what can I check next, can there be anything else than the frame that is causing this non level ride height? The car was level before the incident. Or how to check the frame?

Thanks, Per-Hakan

 

[boomdriver]

If you have a FSM there are measurements in the back section for frame dimensions to cehck for frame alignment.

Usually this is a spring issue. The springs can crack internally and show little or no sign on the outside until they are flexed several inches or cm.

Fronts are very difficult to see because most of the spring is covered. Rears are easy. remove, lay on ground, have someone stand on the spring with the arc upward so that it tries to flatten with weight, look carefully along its length for any fibers that are trying to pop out or splinters trying to separate from the monospring.

If all the suspension bushings have been checked, it has to be a spring unless the frame rails have somehow been misaligned in their parallel position.

 

[vettebuff]

Thanks boomdriver,
The front spring is the only thing that has not been dismounted. However, it was shimed about 1/4" at inner left side (just for testing purpose) but with no change. Of course I have to take the spring off but the car is in garage over winter right now so it has to wait.

You think it still could be the front spring?

 

[boomdriver]

Its hard to say for certain...

I've seen these springs do things that would break a steel spring. They last for years and years under the worst of conditions. But, they can wear out. Eventually they get soft or separate inside. They do not necessarily have to crack or break. I know the softer the spring rate the more arc they have, therefore the further they flex....Not what you;d think as far as wear & tear. The harder the spring the less arc it has, the flatter it is and the less it moves. I have a very stiff rear that probably does not move more than 2" unless I take the car across speed bumps at 80 mph.

I have also heard from more than one owner that replaced his front spring only because they suspected that it was weak and reported back that there was a great deal of improvement in the suspension ride quality and handling. I suppose the deterioration of these composite springs is alot like watching a tree grow.......you'll never see it if you're looking directly at it.

 

[Hib Halverson]

"vettebuff" has established that the car previously sat level, then, after running off the road and into either a ditch or a berm, the car no longer sits level. Further, the car has had some collision repair after that incident which repaired some front end damage.

I think it's unlikely, but possible, that the front spring is a problem. I say unlikely because if it were the front spring, it would seem to me that the difference in ride height would be greater in the front than the rear and the opposite is true.

Nevertheless, I'd inspect the front spring along with all other suspension pieces, front control arms, front and rear knuckles, rear control and trailing arms and dampers.

Next you need to measure the Uniframe as instructed in Section 10 of the factory service manual.

So....what to do if you find problems?

If it's suspension components which are bent, you can replace them then do a suspension alignment.

If the Uniframe is bent you're options are limited. Depending on the nature of the frame damage, it might be possible to repair it. Even if the damage is repairable, you still would have to be able to afford the repairs and find a service facility willing and able to do frame work on that car.

What's my guess on this...

I'd be looking for either a bent rear suspension componentd or a bent Uniframe.

Good luck.