Hey all, this is a long post but I feel it needs thorough explanation.

Front end on my H2 was completely worn out @ 160k miles and it pulled right (remember that), so I decided to do a complete rebuild.

​​​​New parts:
(Rebuilt) Steering box, Pitman arm, Idler arm & bracket, center link, Dmax tie rod ends, upper and lower control arm ball joints & bushings cam bolts, Rancho shocks, Rancho steering damper, sway bar end links.

I got everything together and drove it to get the alignment, drove it home after and noticed it was still pulling right the same amount...

Checked the spec sheet, toe and camber were acceptable but the caster was low, especially on the passenger side (2.5 Driver 2.1 Passenger). Took it back and they refused to touch it, said the adjustment was maxed out and impossible to adjust (?).

Drove to a different Firestone and he was able to get the caster more reasonable, although still low overall (2.4 Driver 2.9 Passenger). Spoke with the tech, he says even thought the caster is overall low, it's not the alignment that's causing the pull, it must be some sort of drag or tire problem. I had already rotated the tires at this point and checked for drag, so his only idea was that the steering box may be defective.

I'll upload a picture of the spec sheets later today.

I've since checked everything I can think of, in order:
-Ripple checked tire pressures, all are perfect.
-All 4 wheels rotate freely with the transfer case in neutral.
-Cross rotated the tires, no change.
-Rotated the front 2 tires, no change.
-Check all brakes and the parking brakes for dragging, none are.
-Checked rear wheel bearings, they're good
Checked driver and replaced passenger front hub assembley, no change.
-Drove the truck down a hill in neutral with the engine off to make sure it isn't hydraulic boost related, no change.
-Swaped CV shafts left to right, no change.

​​​​​It isn't an extreme pull, but it's enough to where you have to point the wheel at roughly halfway between 11 & 12 clock position to go straight. As soon as you let go, the truck will begin moving right and wheel position moves to roughly halfway between 12 & 1 clock position.

The truck drives perfectly other wise.

Any ideas? I've been beating my head against the wall with this for the past 2 weeks... Very aggravating as I can find no cause.

​​​

 

I would take it to a different alignment shop, and ask for a four-wheel alignment. Also ask them to check the front end right height to see if one torsion bar or both need tightened. (My 2003 they determined was sagging in the front almost an inch. They adjusted the torsion bars to bring the height up where it should be, and once you do that it requires a full alignment. I remember the guy commenting that once they got the height right, the camber corrected itself.... And then it needed the toe in adjusted)

 

Note: They do sell adjustable upper ball joints, lets you adjust caster and camber from there. Shouldn't be necessary though.

 

Robert,
That's a good idea, I'll double check ride height. I did make sure to get the bolts even but the truck could be slightly out of level.

I did install standard 0 offset ball joints and bushings.

 

Drive on the other side of the road and see if it does the same thing. These truck do not have enough caster to compensate for the crown on the road. One of my biggest complaints. My truck has always behaved the same way even after front end work. Also I have seen steering stabilizers gassed up so high they cause a pull. Try removing it. Check individual toe. That will cause a pull very easily. Check your wheel bearings too. I have also seen bad brand new ball joints cause the same thing so check them.

Remember that with the suspension design on the h2 you have to check for slop with the front end jacked up by the lca's. If you let them droop, the suspension will be under tension.

I can't wait to swap in my superduty front axle. No more gm ifs BS. Its getting cut in the garage as we speak.

 

I second the disconnect of the steering stabilizer for a quick test. Good luck in your quest to go strait.

 

Gavin, Phil thanks for the replies I appreciate it.

I just got done driving after removing the stabilizer, it made no difference unfortunately.

On a flat parking lot or road it will still pull right.
It only goes straight if I drive on a road with a noticeable and significant left crown, otherwise still pulls right.

I'll report back on the rest.

Yeah I'm not super impressed with this IFS setup. The last 4 (well 6) wheel drive setup I worked on was an m813 5 ton, very different lol.

 

First alignment

Second alignment

 

Yep... Looks like the adjusters on your torsion bars need tightened about half a turn. As they're tightened, it moves the top of the tire outward, which will correct your camber. Most alignment shops don't touch them for some reason. You have to specify ahead of time. Anytime you adjust them it affects the alignment, so things need to be aligned after the camber is adjusted with the torsion rods.

When you get under the vehicle and look at the back side of the torsion rods and see the adjustment bolts, you'll notice there's no method of locking the bolt in place. They are known to back out occasionally. (Red loctite solved that issue for me on one of them)

There's a few things in normal everyday life that will affect the camber of the front end. Putting a lot of extra weight in the back, such as when pulling a trailer. That will take weight off the front, effectively moving the top of your tires to the outside. Adding more weight to the front like a big heavy front custom bumper with a winch, compresses the front suspension and moves the top of the tire inward to the vehicle. In the case of the winch, you adjust the torsion bars to compensate. If you have a lot of tongue weight on a trailer, you just live with it while you're pulling the trailer.

Most high volume alignment shops.... Any of the texts don't know anything about torsion bars, so you need to do your homework. If you can't find an alignment shop that knows how to adjust them, you can easily pick up a magnetic camber gauge. Raise the front of the vehicle so the tires are drooping. Turn each adjustment bolt 1/2 turn, lower vehicle.... Move it forward and backward 20 or 30 ft to let the suspension settle, and recheck your camber. Once you have it on the money, then take it in for a standard alignment. (It does affect the toe in when adjusting.)

 

I mean no disrespect to Robert as he is a very knowledgeable person and helps a lot on the forum.
I disagree with using the torsion bars to set camber,
you need independent scales for each tire and the designated trim height from GM's SI to set the torsion bars correctly, something most DIY's don't have, but using the correct tire pressure and measuring and setting the trim height will get you very close. These settings have a drastic affect on the alignment as GM sets the alignment specs based on a truck at the correct trim height and on a level surface.
One thing I noticed is the Thrust Angle measurement's are all over the place, did they even measure it or is the machine just giving the last know number from the previous vehicle. The Thrust Angle will have a drastic effect on the truck driving straight or pulling to one side of the other. The Thrust Angle is the angle of the rear axle in relation to the centerline of the truck so the front tires need to be set at the same angle to the centerline as the rear axle.
I would think any shop doing alignments knows this and adjust for it when setting toe

Neal