So I went to the alignment shop today and...

They tell me the car is "dog legged" meaning 1 rear wheel is more forward than the other and that I should go to a body shop and have it checked. I don't have a problem doing this but I'm wondering what else could cause this other than frame damage. I bought the car used so anything is possible but after looking under the car nothing looks obvious to me where it had damaged. Also, running a car fax report was clean. I'm just looking for suggestions on things to look at myself. Also, is there anyway I can measure to see the difference for myself?
Thanks
Brian

The car is a 1997 Z28.

Seems like you need an adjustable panhard rod.

You can check how the rear wheels are centered in the wheel wells. Also, compare the gaps around the doors on both sides.
An adjustable panhard bar will not fix this.
A good body shop could probably indentify any damage or work that has been done.

Adjustable LCAs might do the trick.

Thanks for the info so far. Next week I may try a different shop just as a second opinion. Maybe someone can take a look at the page on shbox website. http://shbox.com/1/alignment_specs.jpg .
It kinda looks like one wheel on the rear is more forward than the other? What do you think?

Thanks
Brian

Seems like you need an adjustable panhard rod.

That only changes side-to-side location, not fore to aft.

I'd make sure everything was straight w/ the frame first, then just toss on a set of adjustable LCA's if the frame is okay.

So, I went back to the alignment shop today and told them the frame was straight and asked if we could take another look at suspension parts for damage or wear. Well, the service writter pulls out the work order from last week that has the alignment specs on it (something they didn't give me) and we look at it and I point out that the camber and caster are out of adjustment, but all they set last week was the toe. He then tells me because it's not adjustable. What? I told him that it is adjustable so he goes and looks at the car and says he still doesn't think so. Well, the alignment guy wasn't there so I brought the car back, explained my situation to another service writter who tried to say the same thing, but he went to the tech and low and behold there is adjustment and it calls for a special tool. Great, so now the person doing the work knows (who is a different tech from last week) that this can be done but he doesn't have the tool! So, to make a long story short, to do the job right takes a little more time than most cars and they want to keep it all day. I agree, and I will be leaving it on Monday to let them do what they can. So, moral of the story is that it's good to have a shop manual for one, and two find someone who knows what they are doing. So, we'll see what happens on Monday.

So, I went back to the alignment shop today and told them the frame was straight and asked if we could take another look at suspension parts for damage or wear. Well, the service writter pulls out the work order from last week that has the alignment specs on it (something they didn't give me) and we look at it and I point out that the camber and caster are out of adjustment, but all they set last week was the toe. He then tells me because it's not adjustable. What? I told him that it is adjustable so he goes and looks at the car and says he still doesn't think so. Well, the alignment guy wasn't there so I brought the car back, explained my situation to another service writter who tried to say the same thing, but he went to the tech and low and behold there is adjustment and it calls for a special tool. Great, so now the person doing the work knows (who is a different tech from last week) that this can be done but he doesn't have the tool! So, to make a long story short, to do the job right takes a little more time than most cars and they want to keep it all day. I agree, and I will be leaving it on Monday to let them do what they can. So, moral of the story is that it's good to have a shop manual for one, and two find someone who knows what they are doing. So, we'll see what happens on Monday.

Find a different shop for your alignment. Everything is adjustable front and rear. To much BS from the service people in my opinion.

there are no alignment specs for a solid axle. if you were to get measurements from the wheel well, front, top, and rear, purchase a set of adjustable control arms and panhard rod you could set it back to center and straight. you might also want to check for a bent torque arm.

as far as going to ANY shop looking for an alignment on a solid rear axle, there arent any. it's a solid rear, it shouldnt be out of alignment. camber, caster, and toe should all be 0, +-1 degree. if you still have problems, get new axles and install them. it's probably time for new c-clips any way.

I brought my car to the suspension shop here in San Jose to put all new bushings in the front and they told me the same thing on my car. My car hasn't ever been an a accident before though. The guy told me the rear tracks to the right a little. My car has been in the family since new and there hasnlt been any thing done to the car to permit that. Just to put it on a frame machine is 300-400 dollars plus what they find after that. I wonder if I get adjustable rear control arms that would fix the problem.

Oh and to the post earlier, you can't adjust the rear end demension. My service manual says that if the car doesn't track straight after a front end alignment then that is a indication of a bent frame, lower control arms, or axle housing. I hate to just put adjustable lower control arms in if there is something out of wake in the rear. I guess I'll save my money and have it checked the correct way.

I just looked at GM's alignment specs. Anybody know why GM wants 0.4° positive camber in the front? Was that done as a concession for tire wear, tracking stability or understeer to avoid us F-body crazies from sliding into a guard rail? Or is it a combination of the three? I always thought it looked a tad like positive camber, and now I know it's true. I'll have to change this next time I get an alignment. I'm thinking 0° if not -0.25 on both sides.

So, I went back to the shop today and here is what they did:
alignment specs (http://pg.photos.yahoo.com/ph/briand069/detail?.dir=/6615&.dnm=eb0c.jpg&.src=ph)

I can see where the back is off but tell me what you think. But is this really enough to cause the car to pull to the left? Also, on the way home from the shop my wife watched the car and she said it didn't seem to be "dog tracking". I will probably drive it some more but the pull is still there but not as bad.

Brian

P.S. I found if you hit download on the picture and then open, it will probably be easier to read.

First off, I see you have 1/4 degree thrust angle on the rear. You probably will never notice this or see it when driving down the road. Tire pressure can affect the car more than this. My first question is when they put the alignment heads on the rear wheels, did they jack up the rear of the car and rotate the rear wheels/tires to make sure the heads were measuring perpinduclar to the axle? You can have a bent wheel and if you set the heads up correctly, the bent wheel will not affect the alignment readings. If they did not, this may be what you are seeing with the thrust angle in the rear. The only reason they need to put the rear heads on is to get an accurate measurement for the front as I understand.

I have had several alignments put on my car for autocrossing and have never worried about the rear. If the rear wheels are sitting the same forward / backward from side to side, I'm not worried about it as this is probably the build tolerance during manufacturing. I know my panhard bar or mounts may be bent as the wheels do sit slightly to one side more than the other. I am chucking this up to 55K of very hard driving and autocrossing with slicks. I have not put an adjustable panhard bar on the car yet and probably will not.

If you are having a pulling problem, first check tire pressure, the alignment shop should have done this for you. If that is right and it still pulls, swap left and right front tires side to side. If they are directional, do it when the weather is dry, this is only a test. If the pull moves to the other side, throw the tires on the rear and see if the problem is fixed. Tire wear significantly affects vehicle tracking which I am sure you know. The rear axle is not influenced as much with worn tires as the front. Also, road crown and tire groves in the road can really mess up how the car responds. I have had my car jump sideways about 30 degrees from straight when pulling up to a stop light on a very bad road. The front went one way and the back went the other all because of the road.

The list of things to look at if this doesn't help is very long. Brake drag, wheel bearins, shocks, springs, gosh adjusting tire pressure so the car tracks straight may be easier if the car drives good otherwise. I'm not saying I cut corners because I have spend thousands trying to track down some little problem. Hope you find what the problem is.

Good luck in your search.

Thanks for the response. I don't think the thrust angle in the rear is causing the pulling. From what I have read even if it is off, the alignment can be set to correct it but the steering wheel would be off center. I haven't had time to switch tires yet but I will this weekend. Tire pressure is correct. Also, I measured the wheel base and both sides are equal. I guess if anything I am going to take it to another shop and see what they say after I have some more time checking a few more things.

Thanks
Brian

So,
This weekend I was able to switch the tires on the front and wouldn't you know it, the car started pulling to the right! I even noticed when I had the tire off that it sort of tilted to one side. So off to the tire shop I went and they are going to replace it under warranty since the tires only have about 1200 miles on them. Thanks to all who replied.

Brian