Alignment racks have sliding tables with pins that need to be removed after driving on. After the pins are removed the vehicle is set at the actual angles after jounce the vehicle front and rear. The alignment heads are attached to all four wheels so it doesn't matter how straight the vehicle is on the rack.

 

Perhaps they didn’t take the time to set the heads correctly on the rear wheels.

It took a lot of finicking and multiple days to get mine to drive straight. No alignment shop has the patience. Ultimately this is half the reason I’m solid axle swapping. So over this truck ifs alignment crap.

 

Still working on this,
-Redid all brakes, new calipers and hoses, no change
-Swapped rear axle control arms left to right to rule out them being bent / bushings, no change.

I'm going to disconnect the rear sway bar and try that, but next step I can think of is to order adjustable rear control arms and panhard bar then adjust rear axle.

Don't know what else it could possibly be at this point... Nothing I've done has made even a slight difference in it.

Anyone have an how I can adjust the front end to be biased left to compensate for the pull? I'd rather not spend $800 for rear control arms to find out it's not the problem.

 

add a little positive camber on the right side

Neal

 

Thanks I may attempt to adjust it myself just to test it then get it realigned proper.
At this point I've replaced most every suspension / brake / steering component on the truck so it HAS to be alignment or thrust angle related.

One other thing, I thought a positive thrust angle like mine would cause a left pull? Mine does the opposite pulling right.

 

from the interweb,

A positive thrust angle in vehicle alignment means the rear wheels are angled slightly to the right of the vehicle's geometric centerline, causing the car to "thrust" or steer to the right, which often requires the driver to hold the steering wheel slightly left to go straight, leading to potential "dog-tracking" and tire wear if uncorrected. It's the opposite of a negative thrust angle (leftward) and ideally, this angle should be zero or near-zero for straight-line stability

The front toe has to be based off of the centerline of the thrust angle

A positive thrust angle means the rear axle points slightly inward (towards the vehicle's centerline), and this condition forces the front wheels to compensate by angling their fronts slightly outward (negative toe or toe-out) to make the car drive straight, often resulting in a crooked steering wheel and potential tire wear as the front wheels try to "steer" in the direction of the thrust line. Essentially, the rear wheels "push" the front wheels, causing the front tires to turn away from the thrust line to align with the intended path, creating toe-out to counteract the rear angle

I'm not an alignment specialist but have been doing my own for a good bit,

Neal

 

I would make sure the thrust angle is in fact what is documented before getting to deep into compensating for it. The six link rear is rather stout and i would think a thrust angle that far out would be noticeable with bent parts or very bad bushings.

its a little work but you can check the thrust angle with a tape measure and a chalk line

a good tech and an alignment machine can do much faster

Neal

 

Checking to see if you have gotten this figured out,

I did a little playing with my alignment recently to see what changes effect pulling,
I measured toe, camber and caster prior to making changes, after replacing the steering parts (prior post) my truck pulled to the right slightly, needed fairly consistent correction with the steering wheel.
as found the toe was around a 32nd toe out on the passengers side and around a 1/16" toe in on the drivers side, camber was 0* on the passengers side and -.1* on the drivers side, caster was 4.9* on the drivers side and 4.6* on the passengers side.

I set the toe to very slight toe in, almost no toe, the camber is set to 0* and caster is set to 4.4* on the drivers side and 4.6* on the passengers side, spec says 3.35* drivers side and 3.65* on the passengers side with a +/- 1.00* and a cross caster of -.30 +/- .75*, my cross caster is now -.20*

My truck now drives straight with no pull either way so no steering wheel correction, looking at the settings I think the caster made the correction for the slight pull to the right.

I did check the thrust angle and found around 3/8" positive in 13.6 feet, online converter says that's around .13*, I didn't compensate for this in my alignment

Neal

 

That's extremely helpful information, thank you Neal.

I haven't resolved it yet, but I can use that information to discuss it with the next shop I take it to.

 

Nice. Figures. No shop is willing to do a proper alignment anymore.