So, I get my xj back from the alignment shop and everything checks out A-ok, except for one area. The technician said he couldn't adjust the rear "thrust angle." Should I worry about this? Judging from the shops printout, -0.15* is what the thrust angle should be (to track totally straight). It's "stuck" at .56* .... Despite this problem, the technician said he aligned everything so the tires would wear evenly. The jeep doesn't pull and I have no wobble in the steering.

I just installed a 3" AAL lift kit and 31's. Other than that, the Jeep is totally stock. Has anyone had experience with this before? Thanks in advance.

 

do you have rear coils? i didnt think you could adjust the rear axle on a leaf setup? did he mean right front? if he meant the rear somethings up. or am i wrong school me. lol

 

I have the same issue with mine, the thrust angle is off slightly, haven't noticed any drivability problems or tire wear. not sure if it was really off or just improper set up on the alignment rack......

 

Jeeps are strictly front Toe only, there is no adjustments for caster or camber in the rear or caster and camber in the front. Alignment technicians love when XJ's or other non adjustible rear caster trucks show up for and alignment. They only have to adjust the front toe and set the steering wheel. Easy money for only 15 to 20 min work and still charge the full $60 to $75.

 

First: Thrust angle will not cause tire wear.
Second: Some "Alignment Technicians" will use this measurement to cover up a "drift", "pull" or "cocked" steering wheel issue.

The truth is .....more than 80% of the vehicles on the road have a thrust angle measurement that is not adjustable. Ideally a thrust angle that is closer to 0 degrees will always guarantee a straight steering wheel while going down the interstate. However when this angle is over a degree it can cause handling issues at highway speeds and can even effect how well a vehicle takes turns.
Anything under 1 degree can be compensated when adjusting the steer ahead angles so take no worry mate..........Your Alignment guy was just trying to sound knowledgable or cover up the fact you paid for a "complicated" alignment adjustment that was nothing more than getting the toe angle set.

BTW = I have been aligning cars, trucks and Heavy Duty Trucks for 30 years.

 

Caster is adjustable through the lower trailing arm BTW.

 

Thanks a ton for all the help. You all more than answered my questions and by the sounds of things, I shouldn't need to worry about this issue. I love this forum!

 

there are ball joints available that can correct camber as well. one way to fix the thrust angle is to use adjustable front upper arms. that way, you can use the caster adjustment to set the thrust angle and use the adjustable arms to set caster. thats the way it was done on my cherokee.

zedpapa

 

So after doing my lift and setting my adjustable track bar so the frame is centered over the axle, my steering wheel is now obviously off. When the wheels are straight, the steering wheel is cocked left. I'm getting my jeep aligned tomorrow. Is this something that the alignment people would fix normally? Thanks for the info

 

Yes, they should level your steering wheel when doing an alignment.