dream66

72 Frame leans to the driver side. I replaced all springs and control arm bushings and the darn thing still leans.
Possible causes?
1. Bent lower control arm.
2. Bent or twisted frame

Anyone have a source for a 72 frame datum measurement reference?

cdrod

Here ya go!

dream66

First off - Thanks Rodney for the Datum Sheet.

Local body shop straightened my frame to specs today and I still have rear body lean.
Checked the body bushings and they are within 3/8" side to side
I cant see any twisting of the body itself and the doors and quarters are original.
I guess I'm gonna hafta do some shimming in the left side door to quarter bushings.

oldcutlass

When you replaced all of your suspension components, did you tighten everything with the car supported by the lower control arms in the front and the rear axle? Are all the springs clocked correctly?

dream66

I did not replace any suspension bushings and they look to have been installed during prior owner's restoration 5 or so years ago.

Springs ARE clocked correctly

I just finished shimming the left rear body bushings 3/4" at farthest rear and 1/2" next to wheel house. The body bushings are in relatively good shape - same thickness both sides but I may replace the 2 left rears

When I loosened the bushing bolts, the body rose up on its own on the left rear about 1". This tells me that the left rear 4-5' of the frame is still bent down. This makes sense because we didn't hang a gauge that far back during frame straightening. On the gauges we hung from the frame during straightening they were only 3/8 off ahead of the rear wheels and that's all we corrected.

So now my measurements at the quarter wheel wells are within 1/4" of each other and no noticeable lean looking at the rear from 20' away.

Rocketbrian

I am curious as to how this frame straightening is done, as my 71 442 was hit on the right side, and it sits an 1 1/4" higher on the right rear wheel area vs. the left side. Is the frame marked up to straighten? Is it a simple procedure or is it very finicky and time consuming? I imagine the frame is locked into a position so it can be pressed into spec. Hopefully you have found the solution to your lean.

dream66

It's a drive on dual rail platform. Frame sections are stabilized with chains hooked to the drive on rails and holes in the frame and jacks are placed in areas requiring bending up. Yes the chain hook tension on the frame does bend the circumference of the frame holes some but that can be bent back with a crescent wrench or hammer.

On mine the process took about 3 hours by a guy that knows his $****. It would have taken me 6 to 8 hours to figure out where to chain, where to jack and how much.

Costs can range from $50 to $60 per hour plus a base set up charge of $100 to $200

My solution required some compromising by using body bushing shims but the car is a grocery getter and I can accept a fix short of excellence

oldcutlass

Shimming the body bushings would have been my next suggestion. Glad you got it.

dream66

UPDATE:

I'm postponing front alignment until I get my new steering gear installed but the left side camber is 2-3* out and when that's corrected it may raise the left side up a bit and correct the small variance in the rear.

dream66

Well. shimming 3/4" on the 2 left rear body bushings gets the body close enough, visually, although the measurements at various locations along the quarters are all over the map. Of course now I'll have to wallow out the bumper bracket holes to lift the bumper 3/4" to match the left quarter extension.

I don't like making these compromises to achieve desired visual results but the other alternative is bending the left frame tail up from the axle rearward and that's a really stiff area to bend so I guess I'll settle for the compromise.