I have had the 1970 back together for around a year now (rebuilt non-original frame and non-original suspension) and have just gotten around to trying to align it to drive it to the shop for final alignment. Initial shimming worked well, except that I noticed that there was a problem with the wheelbase on the driver's side being around 3/4 of an inch too long. The passenger side comes right into spec.

I was hoping I could get the difference in wheelbase in true by adjusting the caster on the driver's side but I excessive shimming only brought in a 1/4 inch closer or so. There is no way a shop will be able to get this side adjusted properly IMHO.

I took a good look and noticed that the shock is not centered and the stabilizer bar bolt is at an incorrect angle off the lower a-arm. It is clearly visible that there is a difference in angle between the ps and ds hubs which is definitely causing the wheelbase difference.

The only two things I can think of is that 1) the frame is somehow bent or twisted causing the a-arm to angle wrong or 2)the lower left a-arm is bent. The a-arm is fully restored and painted and does not appear to be damaged.

I assume that the only way to see if an a-arm is true is to yank it off and compare it to one known to be good?

Any other ideas or experience out there with something like this? It would be nice to have something I could really measure before I start popping ball joints.

Thanks

 

i think they make off set A arm shafts.... thats not what they call them but i am habving a brain fart right now

 

Does the front sway bar look parallel to the front crossmember if you look down from the center of the car? If so, I would check that lower arm and also check the frame itself. To check the frame, measure from front to rear on both sides at given points, and then measure diagnally. These measurements should come in within about 1/4" of each other from right to left. If not, you may have a frame which is pushed back on one side(common from front collision that hits only the right or left side of front end). It could also be the mounting bracket on the frame that the lower a-arm bolts to. These always seem to be a weak area and sometimes get broken off in collisions, maybe it is welded back on in the wrong spot.

 

I had same problem check out my threads they may be of help.Buddy 1980 has good points in his reply also.
Mine was a very hard to see buckle of the rear pivot eyes where the bushing goes thru,prob caused in past by a very bad curbing of that side wheel because i later found out that the spare rim was bent (nice of a previous owner!) Dan at Van Steel fixed me up with a new arm fully installed new pivot shaft and everything lined up then.
Excessive shims may be due to frame sag across the top pivot arm towers cure by a spreader bar.but dont expect more than 3 o 4 degree of castor even then.

 

Sorry forgot to mention , noticed your suspension is renewed. These a-arms can be easily buckled if not suported correctly when extracting/inserting bushings thru eyelets in arm.See G.M.chassis manual about this for furthur info.

 

I took diagonal measurements of the frame before I re-mounted the body and everything seemed to line up. For the most part, the car went back together without too much of a fuss including bumper mounts etc. The body mounts seemed to line up just fine.

The sway bar appears to be pretty parallel when compared to the cross member. Its not perfect, but not a 3/4 - 1 inch difference when compared to the wheelbase issue. I have to believe there is a little play with those bushings.

I measured distances on the lower a-arm mounts with factory frame holes and they seem true.

I think this a-arm needs to come off. Something does not seem right about it.

If the a-arm is fine and the frame is bent, I will have 100's of hours down the drain and have learned a valuable lesson.

Oh well.

Thanks for your suggestions.

 

I read through your thread when you were dealing with alignment. The problem sounds similar although mine deals with a wheel base that too long on the the DS.

I just took a measurement from the front of the frame mount under the door to the zirc fitting (lower a-arm) on each side. The DS measurement was 3/4 of an inch longer than the PS. This is approximately the same length as my overall wheelbase problem so at least I have narrowed it down to the front.

I see no visible damage to either the frame, a-arms, or any of the mounts.

Thanks.

 

You have checked the spot welds all around the brackets that the pivot shaft bolts to especially the rear hard to see weld these areas are known to be a weak point if they are fractured the a-arm will "float" around a bit and give variable readings/measurements depending where it settles at the time.

 

P.S. My passenger side was 1/2" longer wheelbase when all this started for me caused by that bucked eyelet, the new a-arm brought it back to 98",the zerk to hole measurements apeared to be the same both sides and the correct lengths but only a SLIGHT difference can produce larger difference else where (its all in the geometry aparently so im told)
When i got the new a-arm and laid it down next to the old one i also noticed that the front sway bar eyelet was up by about 1/4 " not easy to spot without a new unit to compare with i agree.

 

It seems to be in-tract. The wheelbase has been consistently off for quite some time now so I do not feel that there is any "float" at this point.

I agree that a small difference in that a-arm angle can multiply out in the final wheelbase measurement.

I just wish I knew exactly what is "bent" at this point. It is definitely in the front. There is just no visible damage whatsoever. No crumpling, now weird welds, no pinching, nothing to indicate a problem other than the wheelbase.

 

Bump you may need furthur help maybee?

 

Thanks for the bump. At this point, I need to pull off the lower a-arm and go from there. I will get out my protractor and try to record some angles to try and narrow this down.

At this point, my best guess is that the lower a-arm is actually twisted forward based on its angle.

Enclosed are some shots of what I am looking at.









The shock is not centered at all within the spring. It is angled forward pretty bad again pointing to a twisted a-arm or bad frame angles.

 

Those are polly bushings so A-Arm has been off the car.
The pivot shaft looks too new and too clean could that have been replaced?? If the old one was bent or some thing: bet on the a-arm buckled somewhere.
Is the spring properly seated against its seat pocket stop at top and bottom?
Because of poly bushings are you sure the a-arm was supported correctly when the old rubbers were driven out and new poly sleeves inserted. Old rubber units can be a pain to press out and its real easy to cause a buckle when doing this especially when a hammer or press or torch is used without adequate support.see G.M. service manual.
Check the threads and spot weld tabs on A-arm where the base of the shock screws into they are known to come loose or threads go south.
The top ball joint has been replaced and the spindle arm looks like it could have had a work out with a hammer/punch to free original taper,could the spindle arm be slightly bent or have been bent by another impact? back to why the old pivot shaft was replaced here.
just a few ideas to ponder.
regards SAM.

 

From what I can tell, the arm does not apprear to be bent. Couple of things,

Your end link angle apprears to be OK. The suspension is in full droop.

The shock has a t-bar on the bottom. There should be slots on both sides of the t-bar. If the shock was not tighten evenly, the bolt will move the shock in 1 direction vs keeping it centered in the hole.

If the arm was bent, I would seem to think there would be a kink in the arm. I didn't see on from the pics.

Those are rubber bushings, not poly. Energy uses a gold shell, prothane uses a black shell and rubber uses a natural color shell.

Your spring does not apprear to be seated on the bottom. Have you cut coils? It should bottom out just behind the bump stop.

Do you have a pic of the upper a-arm on that side of the car?

How does the channel that holds the lower a-arm cross shaft in place look? Can't tell from pics.

Finally, check to see that the steering column and steering box are in line with one another. If the column is off to the side, the frame is not straight. There will more than likely be a kink in the frame, rear of the steering box and forward of the body mount, visable on the outside of the frame.

Dan

 

Dan, thank you very much for these suggestions. Yes, I cut the springs and will make sure they are seated.

I will try to take more photos of the area including the frame, steering coupling, and lower a-arm channel.

 

I had the same probelm with my car, the forging that bolts to the frame and the A-arm connects to through the bushings was bent. Probably hit a curb sometime in its life. I just bent it back 10 years or so ago and have had no problems.

 

Here are a couple of shots of the general area before I put the body back on. The steering lined up pretty well except for the vertical alignment which I was able to address. I will try to get more.

 

Are you talking about the mount that is welded onto the bottom part of the frame or the pivot shafts mounted within the a-arms? What did you use to bend it back?

Thanks

 

Here are some further shots I took tonight. After looking very closely, it does appear that the frame mount might have been re-welded as the inner weld looks different than the factory spot welds.













Thanks again.

 

I popped the ball joints and removed the spring. It was definitely not seated right with pressure on the rear of the lower a-arm. With the spring out and the hub re-connected, I am currently at around 98.5 inches of PS wheelbase with a few shims in the rear upper a-arm.

I will try to remove the lower a-arm tomorrow to see if I can discover anything.

Again, thanks for the input.