A little background here. I had the front end aligned about two years ago because the tires were wearing on the inside and the look from the front wasn't right. The tires looked out of whack. The shop that did the alignment said it was now good, but the car had an extreme drift to the left. So much so that I have to hold the wheel to the right or I'm crossing the center line.

Today I took the car to a dealer to have it done again. They aligned the front end 4x and it still drifts left. It's not as bad as it was, but still drifts. I know it's not the tires, because I took the tires off the rims and had them rotated. If it was radial pull, the problem would have followed the tire. The entire suspension is original and they didn't see anything that needed to be addressed.

Has anybody else experienced a pull and had it resolved? I know a bent tie rod can cause this, but mine is still factory fresh and the dealer checked 'em. All variables are in spec except the caster. The drivers side is 4.1 and the passenger side is 4.4. That gave them the straightest run while driving.

 

What was the toe? Could you post a copy of the alignment sheet?

 

If I rember right it should be from 4.2-5.3 did you rotate your tires before or after you aligned the car ?

 

 

You are getting rear axle thrust to the right which is causing the nose of the car to go left- especially under throttle. .39 thrust angle to the right is big. Lengthen the left LCA rod end a full revolution it you have aftermarket LCA's. Then go for a test drive and see how much that helps.

You have 0* toe up front. Should be at 3/32 or I think in this BS degree thing they do now on those crappy machines with large user friendly "green" tolerance ranges I think it is .15* inward (you want the center tread of each tire closest to the front bumper 3/32" closer together then the center tread of the same tire near the doors)

You also need a little more caster on both sides. The one in that is not green is not even within their cheap **** tolerances and the other side should be about .3* to .5* more (right side more) for crowned roads- however, the more you do this caster split for the croens roads then the more the car will track to the left ona perfectly flat road. so make sure it stays about where you ahve the split right now but just add about .5 to each side. try for around 5 left caster and 5.3-5.5 right side caster. Caster is what helps a car track straight becasue the chassis weights the wheels to go striaght. The chassis has to lift in order to turn either way so when the caster is low the car will wander on it's own. THis is not causeing the left pull, but it is certainly helping enable it.

They are not showing your SAI or IA which is rediculous. That is what tells if something is bent, not the naked eye. SAI should be close to equal or otherwise a car will pull to one side or the other- most likely part of the problem also.

 

STG, long time no see!

I was gonna say to try 3/32 toe in also but I think you just got much better info than I could offer. I also hate the range the machines say are "acceptable".

 

Thanks for the advice. The car is bone stock, so no aftermarket LCA. I really don't know much about the front end alignment other than what I've read and I don't know the impact that one change has on another as far as Caster and Camber. I know that too much negative/positive caster will wear out the edges of the tires when cornering, but I don't know what too much is. The camber is adjusted via the shock mount, correct? Is this the area that some people say doesn't have enough movement in the mount to get the best suggested numbers? I just don't know why the dealer would have my car for 5 hours and not have any ideas or suggestions on what to fix.

I may get in trouble for this one, but i commented to the service writer that part of the problem might be the car is older than the tech working on it. He said that his master tech was trying to figure it out!

Is there a basic variable that most have found to be correct for caster, camber and toe with these cars? I know the GM spec for my truck is not correct and people have found other specs that work better and allow the tires to last longer.

 

I just pulled the paper from the last alignment. It was because of these setting that the car was pulling left and I took it in yesterday.

Left Front:
Camber - 0.0*
Caster - 4.2*
Toe - 0.00*

Right Front:
Camber - -0.1*
Caster - 4.3*
Toe - 0.01*

Front Total Toe - -0.01*
Steer Ahead - 0.01*

Left Rear Camber - -.5*
Left Rear Toe - -.35*
Right Rear Camber - -.1*
Right rear Toe - 0.19*
Rear Total Toe - -.16*
Thrust Angle - -0.27*

Why is there change in the rear between these numbers and the ones from yesterday? Aren't the numbers static back there?

 

How old are your suspension bushings? I know for a fact (as it happened to me) that if the rubber bushings are worn out, the alignment angles will be different every single time the alignment heads are put on the wheels. Be the time difference a year, month, week, or even an hour, the suspension mounts will shift due to the worn bushings.

Which is one of the reasons why I went with poly bushings. I got tired of the guy running the alignment rack putting the front numbers until they were "close enough".

I wouldn't worry about the rear toe as there is no such animal on a live rear solid axle unless there is a bent axle or rim (and you would know).

 

I'll say this again...The car is bone stock original with 20k miles.

 

And that right there is why I think anybody buying aftermarket LCA's should spend the extra dollars and get adjustable LCA's rather than fixed length. Even if you have no plans to lower the car.



Scott, your camber settings are too tame. Now you're in the minority in that being such a low mile car, you're probably not much at risk of wearing out tires prematurely. But the camber settings should be more negative. Something in the range of -0.3 to -0.5........This will keep the car from wearing out the outer edges of the tires. If you went for something like -1.0 camber, then you'd have to worry about wearing out the insides of the tires. But -0.3 to -0.5 should be easily attainable with the stock upper strut mounts.

The caster split isn't bad. Most shops try and make these the same (they must assume every road is flat and water never runs off the road). You may not be able to get the 5° left and 5.5° right caster with a stock height car. It's easier to do on a lowered car. Basically just have them set the passenger side as far as they can and then have them set the driver side a half a degree less.

You need more total toe in. Recommended 3/32 = 0.09 total toe in. You have none. If you mentally imagine the car's tires toe'ing in, it would seem strange that that would be desirable. After all, shouldn't ZERO toe be perfect? That would seemingly make a car drive straight as an arrow......But rear wheel drive cars when they're going forward, will make the front tires spread apart (thus a toe'd in setup will end up giving you a straight setup)

Front wheel drive cars are the opposite. You set them up for toe out. And then the car pulls the tires inwards, giving you a net straight setup.

A rear wheel drive car with no toe (like your current setup), will end up making the car have toe out when you're actually driving the car. This will give it a zig zag feel over all the bumps and ruts in the road. Not to mention increase the wearing out of your tires.

 

That chart Reid posted is an excellent reference for our cars. He and STG were great help in learning to set up my car. With my new suspension last spring I set up my car with a mild 1/32 toe out so it would be track ready for autoX (even though STG warned me about its streetability) but ended up changing it to 3/32 toe in cause it was shifting from one side of the lane to the other. Just depended on the shape of the road and which way the cracks went. It's much nicer cruising with the toe in.

Check out this thread. https://www.thirdgen.org/forums/susp...ent-specs.html It has some good alignment info but this thread is turning out to be as informative.

Keep in mind rubber has a shelf life. Don't scratch new bushings off your list unless you are sure they are still pliable and aren't dried up and hard. You should have seen the bushings in my 69 camaro when i got it, or what was left of them anyway. I believe they were original.

 

Then just simply buy two new stock rear control arm assemblies. Your originals are shot. That rubber is breaking down and youa re getting even worse thrust angle under power when the bushings collapse.

Lack of miles does NOT mean the bushing are still good after 25 years.

 

Scott was not saying that low mileage equated to bushings that were still in good shape. His comment of it being all original bone stock was to answer the several "well if you have aftermarket such and such, do this."

 

I am sorry but you realy think we did not understand that and needed you to tell us? I was beyond that. Hence why I suggested he buy new OEM replacement units and not aftermarket ones. His bushings are shot and he has no way to fix the problem unless he does so by replacing 20K mile completely stock parts that are 25 years old.

What is both of your points then? and please tell me how I should have responded...Im listening?
...you have a thousnad people in your audience and YOU just stepped up to the mic to give advise on a public suspension forum.

 

I asked the service writer about the bushings when I was there. He didn't believe those to be the issue. I informed him that they are 27 years old and may be culprit, but he assured me that the master tech checked them said they are still tight. I'm suspect that they need replacing. I've replaced the belts, hoses and tires because they got hard and old, so why not the bushings.

Is it a major deal to replace all bushings in my driveway? I've never done it, but I'm willing to if I can. If not, I can get the car to a shop and get it done. What is recommended for replacements, rubber, neoprene or poly? Thanks

Thanks for your advice SlickTrack. 92g92 is on the right track to my response. I saw multiple posts about possible adjustable LCAs and age of suspension components, so my response was regarding the fact that everything is original still. Maybe I should have used that term instead of bone stock. Sorry for the confusion. I will look into replacing all bushings prior to getting the car realigned again. Reid's chart up above should give me a starting point and some of the other details from other posts help a lot. I do know that the Florida atmosphere is very hard on rubber components and I believe that the suspension bushings may be hurting my chances of getting a good alignment. I just don't understand why a master tech couldn't figure this out in the 5 hours that they worked on the car. The waiting room was very boring on Monday.

Any other suggestions or advice? I'm all ears. Thanks guys.

 

Hard to say what did or didn't go through the master tech's head. He may not be all that knowledgable on alignment and the effects of adjustment. As long as he can hook up the machine and make the adjustments the machine recommends, in their eyes, he's qualified!

Anyway, if I had your car I would replace with OEM rubber. it will maintain a quality ride and performance of OEM. I wouldn't bother with any "upgrades" unless you need the added rigidity for performance reasons. I don't think just stiffer bushings alone would make a performance difference you'd notice or appreciate.

 

Full OEM replacement units. Just buy two of these and make life easy. You simply leave the car on the ground and reach under it (on flat ground) and remove ONLY one side at a time and replace it, then go to the other side and repeat. You will have it finished in an hours time even being a novice mechanic in a driveway. No jack or stands required.
http://www.classicindustries.com/cam...rts/g4847.html

 

That's a real ******* comment for no reason, don't you think? I read what you typed as an assumption that Scott was claiming his bushings were good. I am sorry for the misunderstanding; however, if you were a more intelligent human being, you would be able to properly convey your thoughts through text, to all other intelligent human beings, of which I am.

 

I did NOT type an assumption, I typed a fact. He said his car is bone stock meaning original. I told him what is causing his problem and since he is implying he's bone stock I think it is very accurate to read from that he wants to keep it that way.

So...my brain surgeon friend...I quote him and suggest simply he buy bone stock replacement arms with new bushiong already in there.

THEN, you come in right after my post (not quoting anyone else, so aparently you are commenting off of my last post to me) that I am 'Assuming something"? No partner, I am not assuming anything and no you are not smart. I was stating a fact. His bushings are 25 years old and WITHOUT me looking at them I can gaurantee with YOUR LIFE they are not fine,

Good day. How about that for an answer?

 

Your post is filled with fallacy. I DID quote you. My original post was intended to clear some, what I assumed to be, yes, assumed, misunderstandings towards Scott's situation. For that, once again, I apologize. I grew defensive when my less than helpful, apparently, but well intended post was responded to with ridicule of an antagonistic nature. I apologize, although I believe you to be on steroids or testosterone pills for you to react so malevolently (yes, you can Google it, that's alright) to a neutral post such as my original one. I suggest replying more passively and constructively in the future, for the benefit of everyone on this forum.

 

Fuuk you
(Google that)

 

You both sound socially awkward and egotistical. Relax the internet isn't gonna jump out and get you.

To the op, what was the deciding factor to take it to a dealer? If they kept you waiting 5hrs trying to figure out what's up I'd run. There's no master in that tech. Any reputable roundy round or race chassis shops in your area? Your likely to get better results from a shop that specializes chassis building and alignment.
Also,
This is a GM vehicle were discussing here. They havn't exactly been known for their world class quality. Whether your an enthusiast or not you've gotta admit some junk slipped out the door. Its likely it was and has been out of whack when and since it rolled off the assembly line. I wouldn't be surprised if the LCA mount on the diff was welded on in slightly the wrong place. The point is don't discount the improbable.

 

After I went through my steering system by replacing my tie rods, idler arm, and steering box and got some of those fancy tie rod sleeves so I could ballpark them myself, I started getting more adventurous...

I saw a lot of useful methods on the internet to set toe the proper way with old school methods, but I found one method I thought would get me in the ballpark for a while, and that was to run some string across the rear tires and run them to the front. You can watch how they line up across the sidewalls on the front tire whether the tire is toe'd in or out. And it's super easy to check. I've since realized there are a LOT more variables to this than I had originally thought, and it is, in fact, a terrible method. Im not even sure our cars have the same front and rear track. I, in particular, have front wheels on all four corners, so I KNOW my rear track is wider than my front, and that completely slipped my mind at first.

But nonetheless after a lot of trial and error I was able to get both front wheels pretty straight with the steering wheel straight. is it exact? No. Is it close? To the best I can figure, yes. They are at least the same from side to side.

Car veered way to the left with the steering wheel straight.

I know there are variables in this, but I got a good feel for the process while doing it, there's a degree of accuracy I just cant get past, but given the effects of my small adjustments, seeing how far the tires are moving as I adjust them and seeing how small adjustments affect the tracking through my experimentation, the amount of steering input needed to straighten the car after I got the front tires straight was just ridiculous. I knew something else was going on.

Finally measured the rear axle and found that it was definitely not pointing straight forward. The wheelbase on one side was a little shorter than the other... something like 1/4 inch... Which I thought was actually pretty extreme, but whatever, there's a lot of factors in this (I have cut springs and one side doesnt sit quite as low as the other, but springs that sag different amounts on each side will have similar effects, I also ahve LCARBs, and there's no super precise way to install those either, so a lot of things have variables here that can stack one way or another, and who knows if those axle tabs are welded perfectly? Who knows if the hole in the frame is in exactly the right spot?) that will affect the direction the rear tires point. I figured out that the axle was in fact the culprit of the car veering off to one side.

I bought some adjustable LCA's and centered the wheels in the fenders to the best of my ability based on a few different measurements. Repeated my very, very crude toe-method with string across the wheels and got the wheels perfectly straight (I had set both sides an equal amount of adjuster turns to one direction to counteract the axle's angle, which means the car was "sidewinding" to some extent to go straight) and the car drives straight as an arrow now.

Im not telling you get aftermarket adjustable LCA's, just trying to corroborate the previous posts about your rear axle steering the car. Although I thought alignment racks would catch that? But maybe this is where movement in the bushings comes into play? I would see if you can verify the rear axle is 1. pointed straight 2. pointing straight after driving the car around, that is, does it always settle in the same place?

From there you will have a better idea of where to look for answers.

Another thing... I would imagine if the front lower control arm bushings are worn out, I would think they could affect the tracking of the car as well. Removing them isn't difficult, but it involves taking a LOT of things apart and a lot of people have a difficult time installing the springs (I dont, but I dont use spring compressors either, those things are dangerous).

 

Actually it is about the easiest thing youc an replace AND it does NOT require taking apart anything else. You can simply unbolt one arm off the car at a time and replace it before doing the other side...WHILE THE CAR IS WEIGHTED AND ON THE GROUND.

 

I was referring to the front control arms...?

 

My bad, lol. Through you meant the front bushing of the rear arms. Technically the front is an Aarm.

 

I was thinking that might have been what happened. I just hate the term "A-arm" for some reason, but I'll be sure to use that from now on.

 

The term front lower control arm is used often by aftermarket vendors but is not correct. The front upper arm is the control arm and the lower is an Aarm. When the front main lower link is a two point(rather then fixed 3 point) then it is a front lowercontrol arm- when a balljoint makes up the steering knuckle attachment. This type of two piece lower front setup requires a front lower 3rd link arm which mates into the side of that type of lower front control arm (which together make up an Aarm shape.) These are more common on racecars.
http://www.colemanracing.com/Lower-C...gth-P6232.aspx

 

actually he shows a thrust angle to the left as the thrust angle number is -0.39. That could cause a rear steer to the right.

The original specs for toe on the 87 iroc-z is 0.00* with a tolerance of +/- 0.20. I do agree with you on having positive toe.

SAI can cause a pull only at low speeds.

i had the pleasure of working on scott's car today. His car is definitely not the norm when doing alignments. Actually had to put caster lower on the right to stop the left pull. Camber is even at -0.50 for both sides. Left caster 4.40 and right at 4.20. I set toe to 0.09 or 1/16 in. Car no longer pulls left.

 

Here's a picture of his car on the rack today

 

Thanks Robert. The car drove absolutely wonderful on my trip home. I was cruising about 80-85 on I4, the turnpike and the 429 toll road and had no pulling at all. The alignment hasn't been right since 2009 when it was first done with the new tires. Good thing the tires only have 6k miles on them. Time for new ones!!!

 

Glad we were able to get it taken care of for you. Enjoy the ride to the show tomorrow.

 

mrr23, I am going to have to get with you once I finish my front end swap. I have been worried about finding someone that could align my car. Don't really want to take it to just any shop as I know they will do it wrong.


I'm only 45min outside of Orlando.

 

Whenever you are ready let me know. Weren't you on florida thirdgen board some years ago as well?

 

Yes, I was on Florida Third gen. Will PM you when ready.