winkawak

I had my car aligned twice at my local dealer due to car wanders "slightly" left. Steering wheel need to be cocked to the right "slightly" in order to drive striaght. Kind of same ordeal of users on this thread http://www.allfordmustangs.com/forum...out-there.html

Looked over my align sheet and everything is within spec but noticed my thrust angle is at a -.2 degree which is within -.5 to .5 but kinda nowhere near 0. I think thats the reason for my left pull. Search after search i can not find anyone with the same thrust angle as me so im here.

shinerttu

My gf prefers a 45 degree thrust angle! lol, had to say it... I'm sorry I cannot be of any assistance.

winkawak

lol i cant help cracked a smile

Front
Camber left -.7 right -.5
Caster left 6.7 right 6.9
Total Toe .21
Steer Ahead 0

Rear
Camber left -.1 right -.1
Toe left -.19 right .2 (!)
Total Toe 0
Thrust angle -.2 (!)

Norm where are you lol you seem to have good knowledge of alignment.

Norm Peterson

Can you define "slightly" in terms of, say, degrees and direction away from straight or by a required "o'clock" position of one of the spokes?


When you say "cocked to the right", is that a clockwise rotation of the steering wheel as you look at it or is it counterclockwise? Only one way is consistent with the measured alignment data.



I'd really rather see both your cambers closer together even though in your case it would probably exaggerate the error in steering wheel centering.


Either your LCAs are not the same length or there is an error in the location of some LCA pivot bolt hole on either an axle bracket or a chassis side bracket.
Do you have aftermarket LCAs or LCA relocating brackets? Has the car been in an accident or encountered a REALLY bad bump?



Let me think for a moment . . . at 4:28 PM I was on the highway about 15 miles away from my computer. At 4:46 I was 25 miles from home at the local Kenworth dealer helping my son get his stuff loaded into his truck for hopefully a month or more on the road . . . and it was starting to snow. Guess it's lucky for me you aren't in a hurry or anything and I hope that your sense of humor for dry wit is intact.


Norm

winkawak

about 10 degree using this pic
http://www.mathsisfun.com/geometry/i...egrees-360.gif

did spun out once during rain and bump into a curb with my right rear wheel but no frame damage(on frame machine). They replace the right axle shaft, axle housing, right stabilizer bracket, right shock, the wheel/ rotor, pinion nut/seal. The lca didnt bent so they reused it(weird how it didnt get destory like the rest). How can i check if the pivot bolt hole are correct? why is my rear toe negative and postive? also why -.2 thrust?

thanks again for your time

Norm Peterson

The sign convention for toe is positive = in, negative = out. So your left tire is toeing out and the right tire is toeing in. Thrust angle is kind of an "average toe", which in your case is seeing both rear tires toed almost identical amounts in the same global direction (looking in plan view, both are pointing to the left of the vehicle's longitudinal axis). By convention, that is negative thrust angle.


For reasons still unknown, the right end of your car's axle is sitting slightly ahead of the left end, I think by a little more than 3/16". The simplest and probably cheapest "fix" is probably going to be to use adjustable-length LCAs to square the axle in the chassis. No guarantee that this will fix the actual root cause of your axle misalignment, but it'll at least be a decent "Band-Aid" that'll fix the steering wheel being off center and make the car drive a lot better.




Norm

winkawak

still dont get why there toe in the rear when theres no adjustable points.
could right end sitting slightly ahead of left end be normal since there were no frame damage? or possibly installed wrong? upper control arm worn/bent? i dont hear/feel anything wrong with rear when im driving.

Im using this picture and im not seeing anything different than my suspension. Can you name a few possible cause that would have one end sit ahead of other and where should i look exactly? http://cdn.speednik.com/files/2012/06/IMG_8350.jpg

Adj. lca will be last resort, does that mean i have to shorten right end or extend left end? how does it shorten or extend exactly when the two mounting point space between the chassis mount and bracket is fixed. How noisy are the aftermarket adj lca?
also forgot to mention my stock rear wheel are 3/4 of inch difference. driver rear sticks out 3/4 further than passenger rear.

sorry im starting to feel im interrogating you lol

UPRSharad

Even at stock hp, I've seen S197s twist the axle housing tubes. That'll cause a misalignment in the rear end.

Norm Peterson

Something is slightly out-of-kilter.


Do not assume anything here, don't even assume that solid axle cambers have to be zero or that total toe must be zero.



The only way you could consider it "normal" would be if it was "normal for that car" from the day it left the production line. If this is something new since your 'incident', evidently the repair crew did not find everything.


There isn't enough to go on yet - although we know that the right wheel is slightly forward of the left wheel, we still don't know if the right wheel is forward of where it should be or that it's the left wheel that's behind where it's supposed to be. Or if it's some of each.


The report of "no frame damage" - do we know whether that means zero-point-zero distortion or just less than what they'd try to pull out?


Where did they get the axle? I once needed a whole axle swapped into one of my previous cars, and it was almost certainly a "recycled" unit. When I measured it up later, I found about -0.5° camber on both rear wheels, about the same amount of toe-in on each, and virtually zero thrust angle. That was pure good luck. Pure bad luck would be equally likely.


Right side LCA bent
Right side chassis bracket hole moved forward by crash distortion not noticed or reported
Left side chassis bracket moved rearward by crash distortion not noticed or reported
Axle bracket(s) bent
Axle bracket hole(s) not drilled in the right place(s)
Either or both axle tubes twisted - I think I am seeing a fluid leak around the left axle tube where it is inserted into the pumpkin.
It is still possible for the frame to be slightly "diamonded" and all measurements to be within tolerance. IIRC, there is a 1/8" tolerance on body lengths of 100" or more, 1/16" for shorter lengths.




You first have to find out which one is off, and you'd do whichever was necessary. Or possibly a little of both, we just don't know yet.




There is a screw adjustment. A couple different types of adjustment, actually. Look closely at as many of the vendor adjustable LCA pictures as it takes to see what's going on at either end or some place in the middle.

Quote:

also forgot to mention my stock rear wheel are 3/4 of inch difference. driver rear sticks out 3/4 further than passenger rear.

YOU REALLY NEED TO FIX THIS FIRST, before worrying about the LCAs.

That kind of axle shift will add a little thrust angle all by itself, in the same direction that yours is off. It won't be the cause of all of your thrust angle error though.

The first places I'd look are the PHB bracket on the passenger side for being bent and the PHB brace to be bent or slightly buckled or bowed out of straight in the middle. The PHB itself may not be visibly damaged at all. The picture has too much spherical distortion from using too short of a focal length lens to be able to tell any of this, but a right side curb strike would cause these kinds of damage.


It may become necessary to use an adjustable-length PHB to fix this.




Norm

winkawak

If i remenber correctly, the steering wheel was always slightly to right like right now. Didnt really pay attention to the 3/4" difference until after the accident.So i dont know if its like that from dealer.

How did you figure one side rear axle is slightky forward?
When i get home ill try to post my frame alignment paper that was done with laser.

Every replaced part were new and oem. Where is chassis bracket hole? How can i tell if axle bracket hole is drilled correctly? i thought the holes are predrilled.

Ill be adding adj phb in future, warranty is big issue since i have extended 75k miles.

Im currently at a different ford dealer for alignment, talked to the alignment specialist about the rear toe and thrust. He said my rear total toe is 0 so thats good but dont know why thrust is off. He also recommend tire rotation as of right now while adjustin my front total toe to .1×× n steering wheel straight