Alignment on lowered OBS

[Supercharged111]

That's what the Hunter Alignment rack says. My son said I was out of adjustment, even with the knockouts removed. I think he said, if he tries to adjust it any further it would throw out caster, or something like that. He's coming over Monday to help me with the kitchen remodel, I'll ask him again. Like I said, I'm no expert on this stuff, but my truck drives fine

Hunter got it from GM. It's not their fault. I've seen where the factory spec for some of the older stuff only called for 1 degree of caster. 1!!!!!!!!!

 

[PlayingWithTBI]

So if it's not in the alignment, then would it be logical to infer that it must be in the pitman/idler arms, the steering shaft (which doesn't show any wear, it looks like it's been upgraded), or maybe in the tires (doubtful, they are in good shape)?

I think the next logical step is to change the pitman/idler arms.

I'm sitting here with my son talking about your issue. He agrees, it's probably not your alignment, it's more likely a mechanical issue. The 1st thing to check is your gearbox. See how much the input shaft rotates before the pitman arm moves. Then look at your pitman/tie rod ends and clamps. Ball joints are more indicative of hitting bumps and getting wiggling steering, or something like that. We're gonna get back to remodeling my kitchen, HTH

 

[04SVT]

Well, it seems that I need a new steering box. What are folks using as a replacement, a NOS GM unit? Other units? And where are they sourcing them?
Thanks for any suggestions or other info!
KM

 

[PlayingWithTBI]

What are folks using as a replacement, a NOS GM unit? Other units? And where are they sourcing them?

A lot of guys here are using the Red Head box. I will too when my wears out more.

 

[04SVT]

OK, Redhead Steering Gear ordered... fingers crossed on this giving me the steering response that I'm looking for.
KM

 

[04SVT]

Well, after yet another attempt to align this vehicle, I've ended up with .3 and .4 negative camber (from near zero on both sides) and a 'slight' improvement in the drifting left and right, but I'm still not satisfied. I want the truck to track straight ahead, and hopefully have a steering that either stays or pulls slightly back to center.
So my question is would adding more negative camber help achieve this? And if so, are there offset washers for the upper control arm bolts that will allow us to do that?

 

[Erik the Awful]

I want the truck to track straight ahead, and hopefully have a steering that either stays or pulls slightly back to center.
So my question is would adding more negative camber help achieve this?

Caster affects your return-to-center. If your control arm mounts have the tabs knocked out, you can add more negative camber in the rear of the control arm to increase your positive caster - i.e. cant your spindle towards the rear. This give you more caster, but also has a side effect of giving you more negative camber. You'll want to re-check your toe afterwards.

 

[Hipster]

There more to an alignment then caster, camber and toe. There's also Steering Inclination Angle(SAI), Included angle, Turn Radius, And set back. I'm also not a fan of setting one up with different measurements from one side to the other. They should be very close.

Next alignment tell the guy he has to do his job and give you all the numbers.

In a perfect world the tie rods should be as close to parallel to the center link, parallel to the control arms to minimize bump steer. If not there is toe out and in as the suspension cycles through it's travel. Bumpsteer. You can have caster , camber, and toe correct, and have a tweaked knuckle, tweaked frame, or tweaked centerlink that can introduce bumpsteer. The SAI, IA, turn radius, and set back numbers are important when trying to diagnose problems.

You can have bumpsteer issues going straight down the highway at 70 mph is something tweaked.

"The tires look good" is really not good enough here. Tires can look fine and have belt issues internally and drive like shyt. Those issues will normally show up if a road force balance is done.

Finding an alignment guy that knows suspensions is hard to do. Alignment guys that have been trained to work the rack and have little understanding are dime a dozen.

 

[Supercharged111]

There more to an alignment then caster, camber and toe. There's also Steering Inclination Angle(SAI), Included angle, Turn Radius, And set back. I'm also not a fan of setting one up with different measurements from one side to the other. They should be very close.

Next alignment tell the guy he has to do his job and give you all the numbers.

In a perfect world the tie rods should be as close to parallel to the center link, parallel to the control arms to minimize bump steer. If not there is toe out and in as the suspension cycles through it's travel. Bumpsteer. You can have caster , camber, and toe correct, and have a tweaked knuckle, tweaked frame, or tweaked centerlink that can introduce bumpsteer. The SAI, IA, turn radius, and set back numbers are important when trying to diagnose problems.

You can have bumpsteer issues going straight down the highway at 70 mph is something tweaked.

"The tires look good" is really not good enough here. Tires can look fine and have belt issues internally and drive like shyt. Those issues will normally show up if a road force balance is done.

A bent knuckle would show as the delta being different, side to side, between camber and SAI correct?

 

[Hipster]

A bent knuckle would show as the delta being different, side to side, between camber and SAI correct?

SaI and Included angle would both show discrepancies because the upper ball joint would be in a different location to compensate to get camber correct.

Can't stress enough how important those number are to be on the sheet