Rear wheel toe on 90 suburban RWD

[Ricko1966]

.2 degrees is going to be about 1/6th . Take the weight off right rear with a hack. Put your hands at 3 and 9 on the tire push in at 3 pull out at nine and vice versa,do you feel any movement?

 

[richardberg]

The one in black and white is the most recent one.

 

[richardberg]

It’s a 2WD drive yes. I’ve jiggled the front right and haven’t felt any movement to indicate a bad wheel bearing. I’ve spun the wheels and they spin fine. I haven’t done the steering box test. The steering box is leaking oil and I regularly have to refill it.

 

[richardberg]

How did the OP notice the left rear wheel has two tenths of one degree toe out? Pretty sure it's not noticable to the eye or a measuring tape. This whole thread is based on assumptions.

I looked at their printouts

 

[richardberg]

It's hard to say. They should be checked and repacked with grease fairly regularly. It doesn't take a whole lot of difference in friction to cause a pull. The direction it pulls in will be the problem side. The only other thing that you can check that could cause a hard pull is the steering box being out of alignment. The box itself has a self centering function, so if someone did some weird things in trying to adjust the steering box compared to the linkage, compared to the steering shaft, you can end up in a strange state. You can check this by disconnecting the linkage from the pitman arm attached to the steering box while the wheels are pointed straight ahead. Then turn the steering wheel all the way to the left until it stops. Then turn it all the way to the right until it stops again while counting the number of turns it takes. Now turn it half that many of times back to the left and you should be centered. Now go look at the pitman arm and the steering linkage. Do they line up and go together without needing to move the pitman arm? If you need to move something, then it was out of alignment. Adjust the steering linkage arm to the pitman arm until they go together and you should be centered now. You will likely need to adjust the steering shaft or the actual steering wheel now to have it sit straight when the wheels are straight also if you had to change anything.

I’ll try this. Right now the cars is going fairly straight but with alignments totally out of spec to compensate for the pull. Right front is turned in one full turn and front left 0.5 turn out to the left.

 

[richardberg]

sitting in the car I have 1.8 turns to full right and full left, so it seems steering wheel is centered.

 

[Grit dog]

How did the OP notice the left rear wheel has two tenths of one degree toe out? Pretty sure it's not noticable to the eye or a measuring tape. This whole thread is based on assumptions.

I assumed it was based on the printouts he’d been getting from Firestone. Icbw

 

[SquareRoot]

He's since posted those. Now we have something to work with.

 

[Grit dog]

I’ll try this. Right now the cars is going fairly straight but with alignments totally out of spec to compensate for the pull. Right front is turned in one full turn and front left 0.5 turn out to the left.

What’s turned in and out? The tie rod ends?
I may be missing something.

But regardless, I don’t even reccomend Firestone to people I don’t like!

 

[richardberg]

What’s turned in and out? The tie rod ends?
I may be missing something.

But regardless, I don’t even reccomend Firestone to people I don’t like!

Haha yeah I figured Firestone weren’t the best. I very rarely use any shops for anything. Yes the tie rod ends are the ones that I’ve adjusted to make him not pull as much. But of course now the angles are messed up and causing vibrations and a snake drive.

 

[Grit dog]

None of this should cause vibrations.
However snake drive, aka wandering, could have several potential or multiple causes.
Play in steering box and or steering shaft rag joint.
Play in tie rods/ all steering arms (which you may have verified aren’t sloppy?)
Not enough caster. Idk what the spec is for your truck, but looks like you have almost zero positive caster. Feels like it should be more. But I don’t know the spec.

On another note, your rear axle just looks somehow slightly shifted fwd or back on one side. As mentioned, won’t cause pull, it’ll just dog track a little bit. Steering will/should center up to what the rear axle is doing.

 

[Radiohead]

I see the rear axle angles as a normal artifact of use. Probably due to bushing wear, metal deformation from life use. IOW, looks reasonable to me and not causing the main problem.

The caster values are what I see deficient. Both should be a positive value, but the drivers (left) front should have a half degree more positive, to account for road crown. A couple degrees positive caster is plenty.
Keeping front camber even and slightly off of zero is ok as long as they both lean positive or negative.

Thanks for posting the alignment sheets. It's really the only way to assess your situation.

WHEEL ALIGNMENT SPECIFICATIONS | FCAR Tech USA

www.fcarusa.com

On edit - this web page helps explain alignment definitions and gives you an idea what is under consideration on the alignment rack.

 

[richardberg]

I took out the wheel bearing, it looked fine. I repacked it. Perhaps it’s the steering box that’s somehow screwed up.

 

[richardberg]

Can I adjust caster?

 

[richardberg]

Yes I have checked that there is no play in the tie rod ends. There’s play in the steering box though but not terrible for 200 000 miles.