69 Leans After Suspension Rebuild

[Brad H.]

I recently had all the suspension restored/rebuilt by a local restoration company. Everything was new or rebuilt with the best components available. This work included the entire front end and rear suspension. Following this work the car leans slightly to the left (drivers side) about 3/4" lower on the driver side as the right. Are there common mistakes that might lead to this? I would like to be armed with some ideas before I take it back. I have a fair amount of experience with this but elected to have it done this time. I can only think of the left front spring possibly not seated correctly but I'm not really sure what might cause the rear ride height to be lower. I also can not really determine if its the front or rear causing the lean. I really appreciate any ideas here...
Brad

[Terry M.]

Re: 69 Leans After Suspension Rebuild

Yes, seating of the front springs can effect the ride height. It is not just the seating at the lower control arm, although that is the easiest to check. The upper spring seat can be improperly installed as well.

Don't ignore a good visual inspection fo the rear spring hardware as well.

There are instructions for chassis measurement that will remove such factors as different diameter tires from the mix. Study and perform the ride height measurements as described in the Chassis Service Manual. I believe they are also called out in the 1969 AIM as well. They are not easy, but the results will tell you if one or more of the springs (froint or rear) are not up to specifications.

Lastly I believe Joe Lucia had an uneven ride height on his new 1969, and after a thorough and detailed investigation he learned to live with it.

[John H.]

Re: 69 Leans After Suspension Rebuild

Following this work the car leans slightly to the left (drivers side) about 3/4" lower on the driver side as the right. Are there common mistakes that might lead to this?

Brad -

1. Seating front springs incorrectly, especially if the original springs have been replaced; the springs are to be seated at the UPPER end, 3/8" from the formed stop in the upper spring seat in the frame, as shown in the Assembly Manual. The hole in the recessed area in the lower control arm is there for water drainage, not for spring seating.

2. Torquing front upper and lower control arm bushing bolts with the car on a lift and the front suspension hanging in rebound; those bolts must not be torqued unless the car is on wheels at normal ride height.

3. Torquing the rear trailing arm pivot bolts and the inner and outer strut rod bushing bolts with the car on a lift and the rear suspension hanging in rebound; same requirement as the front suspension.

[Brad H.]

Re: 69 Leans After Suspension Rebuild

Thanks Terry,
The car did not lean prior to "suspension restoration" and all the tires are the same and new. I will have them take a closer look at the front spring seats. Also, the rear spring is the original and was taken apart, blasted, painted, and put back together with new insulators and all new hardware. Is it possible for the rear spring to sag on one side and not the other over time and if so is there a way to correct for it somehow on the low side?
I really appreciate your help!
Brad

[Brad H.]

Re: 69 Leans After Suspension Rebuild

Thanks John, I'll check all that. I really appreciate it!
Brad

[Edward J.]

Re: 69 Leans After Suspension Rebuild

Brad, to add to Johns post, I think I remember reading in the shop manuel for my 72 that the drain hole in the lower control arm is about where the other end of the lower spring will end up if the upper spring is seated correctly. after market springs may or maynot be wound in the same position as the factory.

[Joe L.]

Re: 69 Leans After Suspension Rebuild

Thanks Terry,
The car did not lean prior to "suspension restoration" and all the tires are the same and new. I will have them take a closer look at the front spring seats. Also, the rear spring is the original and was taken apart, blasted, painted, and put back together with new insulators and all new hardware. Is it possible for the rear spring to sag on one side and not the other over time and if so is there a way to correct for it somehow on the low side?
I really appreciate your help!
Brad

Brad------


Are you sure? I can tell you this: my original owner 1969 convertible "leaned" just about exactly as you described from DAY ONE. The GM service representative, called out to check the car per my complaint at the time advised me that it was within factory tolerance and that any "lean" was not the result of any suspension abnormality.

Many years later I completely rebuilt the suspension and it did not change the "lean" by one iota.

[Wayne W.]

Re: 69 Leans After Suspension Rebuild

Brad, to add to Johns post, I think I remember reading in the shop manuel for my 72 that the drain hole in the lower control arm is about where the other end of the lower spring will end up if the upper spring is seated correctly. after market springs may or maynot be wound in the same position as the factory.

If the springs are made correctly the end positions top and bottom are always in the same relative position.

[Brad H.]

Re: 69 Leans After Suspension Rebuild

I really appreciate all your thoughts on this lean issue. In response to Joe's question, the car didn't lean before I had the suspension rebuilt. The front springs were replaced with Corvette Central reproductions and could be suspect I suppose (the originals had twist in spacers to raise the spring height back up). It really does lean however both visually and by measurement. I'm not sure what the factory limits were, but I suppose if the tolerance for the right side were at the upper limit and the left side was at the lower limit then it might add up to driver side lean and actually be "within factory limits". Anyway, I appreciate all your thoughts on this. I'll start checking into your suggestions and let you know if I stumble on the reason. Anybody have any thoughts on the rear spring? Meanwhile if anyone thinks of anything else, I certainly do appreciate your inputs!
Thanks again!
Brad

[Joe L.]

Re: 69 Leans After Suspension Rebuild

I really appreciate all your thoughts on this lean issue. In response to Joe's question, the car didn't lean before I had the suspension rebuilt. The front springs were replaced with Corvette Central reproductions and could be suspect I suppose (the originals had twist in spacers to raise the spring height back up). It really does lean however both visually and by measurement. I'm not sure what the factory limits were, but I suppose if the tolerance for the right side were at the upper limit and the left side was at the lower limit then it might add up to driver side lean and actually be "within factory limits". Anyway, I appreciate all your thoughts on this. I'll start checking into your suggestions and let you know if I stumble on the reason. Anybody have any thoughts on the rear spring? Meanwhile if anyone thinks of anything else, I certainly do appreciate your inputs!
Thanks again!
Brad

Brad------


It's possible that someone previously made suspension "adjustments" in order to correct the "lean". In other words, made the suspension "high" on one side so as to compensate for body "lean" on that side. The fact that you had coil spring "twist in" spacers on the car might indicate this. Were there the same number of spacers installed EXACTLY the same on both sides.

What about the rear suspension? Were there non standard spring outer bolts used and/or were there spacers (i.e. extra flat retainers) installed on one side?

"Re-jiggering" and rendering asymmetric the suspension is one way to correct body lean, but one is far better off leaving the lean than doing this to correct it.

If you want to determine now if the "lean" is in the suspension or the body-to-frame mount, measure the various suspension dimensions as shown in the Chevrolet Service Manual or AIM. If they are within specifications, then the "lean" your car exhibits is not in the suspension. That's another thing that I did years ago to my car. I found that the suspension dimensions and inter-relationships were near perfect. Therefore, the "lean" had to be in the body-to-frame mounting and had nothing to do with any suspension problems.

Trying to "correct-out" a "lean" due to body-to-frame mounting is something that you don't even want to think about getting into.

[Brad H.]

Re: 69 Leans After Suspension Rebuild

Joe,
Thanks for that. I really didn't check the exactness of the front springs spacers when I removed them and I didn't keep them to look at them now (pretty stupid on my part, I know). As for the rear suspension, we saw no sign of any tampering back there and it looked very original. Its hard to tell if the lean is originating from the front or the back or maybe its neither as you say. You answered my next question which would have been if there was a way to "shim" up the left side to increase the ride height on just one side. Sounds like if I don't find anything obvious in the suspension out of whack, to just quit worrying about it.
Thanks again for your input.. some things are best just left alone.
Brad

[George C.]

Re: 69 Leans After Suspension Rebuild

Brad,

Are the bolts the same length, and have they been tightened equally? Seems to me when I put my new spring in one or two revolutions made a difference in ride height.
George

[Brad H.]

Re: 69 Leans After Suspension Rebuild

Thanks George,
I was wondering about that sort of thing. Can you change the rear ride height by changing the length of the bolt, etc?
Brad

[Joe L.]

Re: 69 Leans After Suspension Rebuild

Thanks George,
I was wondering about that sort of thing. Can you change the rear ride height by changing the length of the bolt, etc?
Brad

Brad------


Definitely. In fact, that's how GM did it during the 76-82 period when bumper height became critical due to federal regulations. Several slightly different length bolts were available in PRODUCTION for this purpose.

However, there is essentially no adjustment available with stock GM bolts. They are designed so that with the proper slotted nut installed, it has to be turned all the way down against the collar on the bolt in order to install the cotter pin. With aftermarket bolts of substitute design adjustment is possible, though.

[Brad H.]

Re: 69 Leans After Suspension Rebuild

Thanks Joe,
I'll look into that as well.
I appreciate your help as always!
Brad