Front Suspention (air-ride)

Have you changed the tires? They probably wore to the old worn out parts.

Did they align just the front or the rear too?

Any play in the steering?

 

I'd have to say that's BS. Put an 1/8th inch shim in the right front drive wheel position and your problems should be over. The problem is they have it aligned perfectly for a flat surface, which highways are not. The road is crowned to the right and you need to change the thrust on the drivers from thrust neutral to thrust left, which the shim I suggested will do. If the 1/8th shim is too much or too little, adjust the thickness accordingly, but my experience is that 1/8th is about right.

 

You might also want to change the steer tires from side to side. If you have a belt problem with the one on the right, it will pull that direction. If the pulling changes with the tire change, your problem is at least partly tire related, probably caused by the thrust problem.

 

Is there a leveling valve for each airbag on the steer axle? Have you had the ride height checked? If neither of those then I would say the problem is not related to the suspension.

 

There is a leveling valve for each airbag. My truck does the same thing. I think it was wrecked before I got it and may have slightly bent the axle. They can't bend the Hendrickson axle so what ever it is, is the way it stays unless you buy a new one.

 

I have an air-ride front end on my truck. I do all of my own axle alignments, and always have done so. First off, most 'pulling problems' on air ride front ends are actually the rear axle alignment. Both rear axles can be straight with each other, but the pair need to be offset from the front axle. When they are straight with the front, this will cause pulling due the offset in the front caster required. Air ride front ends have a much higher caster angle, making rear axle offsets much more noticeable. That higher caster makes the sterring want to sit in only one place going down the road. if that place is not the exact correct spot for a straight line + road crown, then you will fight the steering all day long via a pull. First thing first, shift BOTH rear axles to the right about 3/8 inch for an air ride front end, then parralel with each other (passenger side further back toward the rear of truck than drivers side). This will help alot, and is the best correction for crown in the road on a air-ride truck. My drives had 427k miles on them with no wear patterns set this way when they finally had less than 6/32 tread, so NO it will not cause excess drive or steer tire wear. Start here, and if it clears up the pulling, then your done, but if it still persists, the problem is that your Caster alignment is off as well. For an air-ride front end, it should be about 5-6 degrees on the drivers side, and about 7-8 degrees on the passenger. This is much further than the traditional +3-4 degrees you see on spring front ends, and many alignment shops do not know this. I say the caster, because the bushings in the suspension wear down as the front end ages. This creates the problem of the caster getting more and more off as it ages. The side that wears the fastest is the drivers side, because of the lower angle (more stress to the bushings). Just shimm the lower arm to get the caster back to about 2 degrees less on the drivers side, than the passenger side, and the pulling will stop. This assumes that the air-bags and leveling valves are set correctly first. They can cause the same problem. Just meaure the shocks on each side from the base to the joint where they move up/down on each side. If there is a difference in height, adjust the leveling valves accordingly. Also ensure the bags aren't over or under inflated as this effects the caster angle as well.

On a air-ride front end, TOW ALIGNMENT WILL NOT CAUSE PULLING!!!. It will simply cause your tires to wear either from both insides outward, or from both outsides, inward. Replacing tie-rods will not solve ANY pulling problems on an air-ride unless it is actually bent severely and eating tires up at a rapid rate.