Basic Do-it-Yourself Jeep JK Wrangler Front End Alignment

WJCO

Meme King
Is caster relative to the angle that the frame is. I have the RK 2.5 max travel, stock bumpers and the rear sets high.
89* garage floor angle
91* frame and roof
90* bolt hole on front axle
96* top of ball joint
2* rear drive shaft / pinion difference
If the rig is loaded and level does that change the caster.
I see a caster of +7*. Is that correct .

It is relative to the angle of the frame/ground/etc. If you have 96 on the ball joint, and the ground the Jeep is sitting on is zero, then you have 6 degrees caster. I like parking it on clean cement and measuring the ball joint, then measuring the concrete right under the ball joint. So if I were to get 96 at the ball joint and 1 on the ground, my caster is 5.

EDIT: Sure looks like you have 7, but that seems like a lot. I'm guessing your lower arms are adjusted too long.
 
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Thanks!!!

Adjusted the caster and centered the steering wheel. Drives so much better with the correct caster! :thumb: Have an adjustable track bar on order so I can fix the axle offset.

Thanks for the help, great write up!
 

jiip20

New member
2017 Jeep Wrangler JK Help setting my caster

So, I had a 3.5" MC lift put on with some 35/12.5/17 Nitto. Steering has a really scare wandering sensation when driving a highway speed. My lift includes adjustable front upper CA. This was the report I received on the alignment. Anyone have any input on this?

Also, I was trying to get the caster angle on my driveway but I got different numbers.

thumb_002_1024.jpg
Top of the ball joint_01.jpg
Flange.JPG
Edge of the differential Housing.jpg
 
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WJCO

Meme King
So, I had a 3.5" MC lift put on with some 35/12.5/17 Nitto. Steering has a really scare wandering sensation when driving a highway speed. My lift includes adjustable front upper CA. This was the report I received on the alignment. Anyone have any input on this?

Also, I was trying to get the caster angle on my driveway but I got different numbers.

View attachment 245209
View attachment 245218


Based on these pictures, it looks good. You want it around 4.5 on your ball joints (assuming your garage floor is at 0). I can't really see the gauge in your picture, but if you're just under 5, you're good.





^Don't do this, that yoke is round and won't give you a good reading, the angle finder has to be on something flat.
 

wayoflife

Administrator
Staff member
Based on these pictures, it looks good. You want it around 4.5 on your ball joints (assuming your garage floor is at 0). I can't really see the gauge in your picture, but if you're just under 5, you're good.

Agreed. Looking good with this.
 

jiip20

New member
Caster Angle Adjusting Part # 2

Guys, I just realized that I am getting a negative caster angle, (Please correct me if I am wrong on this) please see attached picture where the angle is between 4 and 5 degrees. So I wonder what are my options in order to bring my caster back to spec? Considering that I installed adjustable front upper control arms, so what should I do shorten or lengthen them.

Caster angle readings.jpg
 

WJCO

Meme King
Guys, I just realized that I am getting a negative caster angle, (Please correct me if I am wrong on this) please see attached picture where the angle is between 4 and 5 degrees. So I wonder what are my options in order to bring my caster back to spec? Considering that I installed adjustable front upper control arms, so what should I do shorten or lengthen them.

View attachment 245581

Nope. That's 4 positive. It's good. Positive caster is where the upper ball joint points toward the rear of the jeep, so it's correct. Negative caster is where the upper joint points toward the front bumper.
 

Ddays

Hooked
So just for shits & giggles I went out & checked my caster. Haven't really done that for quite a while. I'm at 94*

0223172108a.jpg

I'm really curious if I'll be able to tell the difference once I dial it in at 92*
 

WJCO

Meme King
So just for shits & giggles I went out & checked my caster. Haven't really done that for quite a while. I'm at 94*

View attachment 245591

I'm really curious if I'll be able to tell the difference once I dial it in at 92*

Is that on your LF? That can't be right. Check the angle of your garage floor and subtract. And make sure the surface of the ball joint is really clean.
 

Ddays

Hooked
Yes. At least is was supposed to have....

Edit: the little light just went on upstairs....BRB


Yup, different on the BJ. pain in the ass to get it on a flat spot on the Prosteers tho..

BJ.jpg
 
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WJCO

Meme King
Yes. At least is was supposed to have....

Edit: the little light just went on upstairs....BRB

Eddie's write up won't give you the same number on your gauge in regards to this axle as Dynatrac sets the pinion angle differently. So you need to compare the top of a ball joint to the ground itself for your actual reading
 

Ddays

Hooked
Eddie's write up won't give you the same number on your gauge in regards to this axle as Dynatrac sets the pinion angle differently. So you need to compare the top of a ball joint to the ground itself for your actual reading

Floor is nice & flat concrete.
 

WJCO

Meme King
Yes. At least is was supposed to have....

Edit: the little light just went on upstairs....BRB


Yup, different on the BJ. pain in the ass to get it on a flat spot on the Prosteers tho..

View attachment 245599

It is hard to measure on those. If you're happy with the handling, don't tweak it anymore. I think you should be closer to 6 (84 on gauge), but if it ain't broke, don't fix it.
 
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