West Coast GTA Man

Hey Guys,This is long, but please read. some of you may not know, but I spent About $1200 on new tires, shocks, struts, springs, bushings and an alignment. Well the place I took it for the alignment & tires is very reputable. The car was done and it pulled to the right, so I took it back and it still pulled a little bit. I took it back again and they said that did a special alignment called a SAI alignment. They said they do this on cars that have been wrecked, frame damage, etc. Well My car was never wrecked. I had it checked by the Vin # on Carfax, and to a dealership body shop that a friend works at. The only thing done was the drivers fender was creased and changed. No hood or door damage (Very Minor). Well after they did this alignment they said that the rear right wheel toe was out. It was Neg-0.30, and that there is no way to adjust this. He said that is what is causing the pull to the right. He said as far as he knows, that the only way to fix this is to put it on a frame machine and have it fixed. He said that it most likely is from torque over the years. The left wheel toe was 0.12. He said the right wheel is off about a half inch. Is there any way to adjust this???????? Sorry this is long, but this is bothering me!! What gets me, is after they aligned it today again, it really doesn't pull at all anymore. But they go ahead and tell me this stuff. If it has to go on to a frame machine, about how much should it cost me, and will they be able to get it right to factory specs?? Please help Guys!!!!
Thanks
Mike

TVP

if the right and left are at different numbers ... i'd suspect the
axle housing is bent ..not really the frame ... which sounds like the case ..especially since the right is more than the left .. non-posi rear :\ if you had all the spohn peices you could adjust
the LCA's and square up the rear ... but then the left would be zero and the right would still be .2 ???

West Coast GTA Man

Thanks for the info TVP! I appreciate it man. Is this still the case being that I have a Posi rear? I noticed you said somethng about non-posi, but I didn't undersand it. Thanks again man!
Mike

mrr23

no. what you are adjusting is the thrust angle of the rear. thrust angle is zero when toe is equal on both sides. so when thrust is zero, then his toe will be 0.10 on both sides.

DAVECS1

iTrader: (2)

I highly doubt your axle is bent or the housing it is in. If this is the case. Your car would vibrate enough to knock the teeth out of your head or the axle would eventually snap. It would be helpful If you posted the measurements of the front wheels after they aligned them. They should of gave you a sheet with these specs. There should be three specs: Camber, Caster, and Toe. The most common mis adjustment is caster. Most shops set this so it is the same side to side. This will cause the car to wander towards the ditch. Taking into acount the road is crowned in the middle and that the drivers side is heavier because you are sitting in it means that the passenger side should have about .5-.3 degrees less caster. To prove to yourself that the rear is ok you can take a measurement yourself using a good quality tape measure. First jack the car up so the rear axle is in the air and you can spin the wheels freely. Next pick a tread groove in each wheel and mark it so you measure to the same groove every time. Now you want to measure from the front of one wheel to the other being carefull to keep you tape as horizontal as possible. Now rotate the wheels a 180 degrees and measure from the rear of one wheel to the other. You should find that the two measurements are extremely close and that you have nothing to worry about. Good luck and keep me posted

West Coast GTA Man

Great advice DaveCS1!! I will try that this weekend also, and let you know. It seems to make sense. Thanks again.
Mike

mrr23

you want the caster to be about .5 degrees lower on the driver's side with the driver in it. a car pulls to the lower caster number. the road crowns to the right. so the offset of caster will compensate for that. now for camber, you would want the driver's side higher than the passenger side. a car will pull to the higher camber.

TVP

mrr23 ... if the thrust angle was off ..wouldn't the numbers be off the same amount on each side .. i.e. .. .1 left and .1 right .. since they are off .30 and .12 .. he centers the .12 and ends up with .18 on the other side ????? a straight rear should 0 toe 0 caster 0 camber ..right ???

usually a non-posi car will plant it's torque on the right side
wheel .. over years of ab-use that axle tube will pull forward ..
hence the "toe" in the rear ... same thing will happen if you curb it :\ .....

For an actual easy way to check out a car for alignment ... no jack required !!! use the old fashion "string" technic ... I use 4 - 5 gallon buckets to frame a car ..i.e. one at each corner .. then run a string around the buckets ..tightly .. sagging suxs .... adjust the strings so they are parallel . to do this ..generally on a stock car .. you can measure from the center of the wheel on front and rear ( ***-u-me-ing the car has equal track width front and rear !!! ). this ensures that the string is parallel to the side .. then measure the front and rear distances between the stings .... if they are the same your car and strings are now tangent ... from here you can also check the toe angle or "distance" by measuring the front of a wheel compared to the rear .... then with a plumb bob you can check the camber I use a microphone stand for this



TVP

mrr23

yes. i talked with him today. his thrust angle is .21 the left toe is .12 and the right is -.30. what you do is add the two numbers together and divide by two to get the thrust if they aren't equal. .3 + .12 is .42/2 = .21 thrust. now to determine which way the thrust is look at which way is nore negative. so the thrust is to the right. total toe is add the two numbers together. -.3+.12 = -.18. now to get the thrust angle to 0 the toe needs to be equal on both sides. take -.18 and divide by 2. you get -.09 each side. when you get toe equal on both sides, then the thrust angle is 0. rear is straight with the geometric centerline of the car. this gets rid of the 'dog leg' look when your behind a car.

a straight rear would be 0 camber and toe. but the manufacturer builds a certain amount to aid in handling. plus things like welding the axle tubes to the center chunk and things like that will make it vary. trying to find thrust angle by measuring center of front wheel to center of rear wheel doesn't work because of a multitude of things. one being setback up front. this is one wheel being ahead of the other. mine has a setback of .09. that means the center of the right wheel is behind the left. when you do this, the rear now has a thrust angle of .09 to the right, assuming the center of the wheel is actually geometrically in the center.

anyways, the alignment shop was blowing smoke about the rear being bent. his total toe is -.18 which is -.09 each side when the thrust is 0. he has a tire pull. and now it wanders because they put -.9 cross caster. so it pulls left and the tire pulls right. so he gets wander.

dman this is long i'll stop now.

West Coast GTA Man

First of all I want to thank everyone for helping me with this problem. A real big thanks to you Mrr23! I am going to swap the two front tires this weekend and see what that does. I will be getting the Panhard Bar you recommended along with the trailing Arms real soon. Then I will take a cruise up to see and have you line her up fo me, and probably install the parts, unless they are real easy to do. Man you know your Alignments bro!!! Thanks again for the help today, you put my mind at ease about the frame worry!
Later
Mike

mrr23

they are easy. 18mm wrenches for the trailing arms. 18mm and 21mm for the panhard rod.