389 Steering Problems

**Ebb75** · 08.28.2012

Hi im new to the forum. One of our petes has a steering issue that we cant figure out. Its a 2012 389. Has steering axle air bags. Seems to jerk the wheel pretty good when any bump in the road is hit. All steering components are tight. Replaced steering box. Tried new steer tires. Tried different air bag pressure in the front. Nothing is working. Just wondering if anyone else had this problem. As none of the other trucks in the fleet do this.

**flc120** · 08.28.2012

wowsers 2012!!! truck with issues holy crapper...

you replaced gear box? wow do the other trucks in fleet have front steer axle airbags? could be just the normal feel of the airbag front suspension.Although i drove a 379 pete with front air bags and never felt this before.

maybe its a manufacturer recall.

**Ebb75** · 08.28.2012

Yes we have another with front air bags and dont have this problem. Dont know what else to try. Maybe the pump off the engine that feeds the steering box is surging or something. Its a puzzle to everyone.

**DL550CAT** · 08.28.2012

Make sure the axle is not in backwards. I know of a older truck that had the axle replaced and they put it in backwards. He drove it for a month like that. He said it never felt right and that it was jerky.
I am almost positive that the ID tag is supposed to be toward the front. Maybe check your other trucks to be sure.

**Ebb75** · 08.28.2012

Thanks DL550CAT will check it out.

**Heavyd** · 08.28.2012

If you have a Hendrickson Airtek axle, this is one of the characteristics of this axle. It is more "springy" than a regular cast axle. Hendrickson was placing a composite thrust bearing on the left side of the axle to help dampen the shake you are experiencing. You will need to check if one side thrust bearing looks different than the other side, if they are both the same chances are you need one installed. We had one customer a few years ago with brand new unit with an Airtek and we replaced everything bolted to that axle. We played with the caster settings and nothing changed nothing. The rep from Hendrickson had to come down and road test the unit. After he drove it they authorized us to replace the whole beam. The beam wasn't tempered correctly. After that it was better, but still had some shake. We ended up installing a steering stabilizer and the customer was happy after that. We still see that same truck today, with a different owner, but everytime I drive it it still has that little shake.

**GP1500SC** · 08.28.2012

Is the ride height set correctly?
its probably not the problem, but is a easy check and it will cause bump steer if is to far off.
the bar off the pitman arm going back to the axle should be level.

**Ebb75** · 08.28.2012

Hmmm good to know. Maybe it will always have that little shake. Ill do some investigating. Thanks for everyones input. Greatly appreciated.

**Ebb75** · 08.28.2012

The drag link should parallel to the ground is what your saying GP1500SC?

**GP1500SC** · 08.29.2012

Correct, except on the previous post I left the little word about out in front of level
A rise to the front is normal and necessary , especially with springs as ride height is dictated by load, air ride not so much.
The higher the rise / angle the more the the truck will steer to the right as the body goes down in a bump situation, or body roll.