Question about DIY Alignment Guide

theprez

New member
Hey All-

Although I just recently had my JK aligned professionally, upon reading this link it seems fairly simple:

http://wayalife.com/showthread.php?3861-Basic-Do-it-Yourself-Jeep-JK-Wrangler-Front-End-Alignment

One question I had was on taking the caster measurements - either on top of the ball joint or the other location mentioned. While the write up doesn't specifically mention checking both sides id assume that's what's needed?

In other words, the goal is positive 4.2 degrees when measured from the top of the ball joints on both the driver and passenger side with an angle finder/protractor - so adjust the arms whichever way (shorten or lengthen on each side) until you get 4.2 degrees on both sides.

Is that correct?

- Once I better understand this, ill likely be doing my own alignments :)
 

WJCO

Meme King
Hey All-

Although I just recently had my JK aligned professionally, upon reading this link it seems fairly simple:

http://wayalife.com/showthread.php?3861-Basic-Do-it-Yourself-Jeep-JK-Wrangler-Front-End-Alignment

One question I had was on taking the caster measurements - either on top of the ball joint or the other location mentioned. While the write up doesn't specifically mention checking both sides id assume that's what's needed?

In other words, the goal is positive 4.2 degrees when measured from the top of the ball joints on both the driver and passenger side with an angle finder/protractor - so adjust the arms whichever way (shorten or lengthen on each side) until you get 4.2 degrees on both sides.

Is that correct?

- Once I better understand this, ill likely be doing my own alignments :)

Yes. You will have to adjust both sides until you meet the desired measurement. I would recommend using the protractor first on your rock slider or frame and see what your actual vehicle is sitting at as ground isn't always perfectly level. Then take that into account when you set your actual caster too. Example, if your entire vehicle is setting on a 1 degree surface, make sure you subtract/add that from your reading on the ball joint to obtain the desired number. The ball joint location will work fine as long as they're clean and free of mud, etc.
 

wayoflife

Administrator
Staff member
Hey All-

Although I just recently had my JK aligned professionally, upon reading this link it seems fairly simple:

http://wayalife.com/showthread.php?3861-Basic-Do-it-Yourself-Jeep-JK-Wrangler-Front-End-Alignment

One question I had was on taking the caster measurements - either on top of the ball joint or the other location mentioned. While the write up doesn't specifically mention checking both sides id assume that's what's needed?

In other words, the goal is positive 4.2 degrees when measured from the top of the ball joints on both the driver and passenger side with an angle finder/protractor - so adjust the arms whichever way (shorten or lengthen on each side) until you get 4.2 degrees on both sides.

Is that correct?

- Once I better understand this, ill likely be doing my own alignments :)



The easiest and probably the most accurate place you can get a reading is on the face of one of the large holes located on the edge of your differential housing. This is the location of where a case spreader would normally go. When set correctly, your angle finder should be sitting close to vertical with a reading of 92° or 88° here.
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Do NOT concern yourself with what one side reads versus the other as you are dealing with a SOLID front axle. You will NOT be able to effectively adjust one side or the other nor should you try. The readings you got from the alignment shop would be informative IF you had an IFS or even an IRS.
 

theprez

New member
Awesome this makes perfect sense now. One follow up - why the difference of either 92 or 88? Seems like it would be one or the other but I'm just a rookie at this stuff ;)
 

wayoflife

Administrator
Staff member
Awesome this makes perfect sense now. One follow up - why the difference of either 92 or 88? Seems like it would be one or the other but I'm just a rookie at this stuff ;)

I think you're just over thinking all this. It just depends on how you've got your angle finder setup. Place it one way and it will give you one reading - place it the other and you will get a different reading. In the end, you just want to see a 2° change. Does that make sense?
 

WJCO

Meme King
Awesome this makes perfect sense now. One follow up - why the difference of either 92 or 88? Seems like it would be one or the other but I'm just a rookie at this stuff ;)

It's just the way the angle finder is sitting based on the ground he is parked on. It could change if the ground isn't level. It needs to be close to 90 in that location or zero if placed on a ball joint. Also Eddie brings up a good point about one side vs both sides. You can't really independently adjust both sides with the solid axle. I always check both sides anyway, guess I overlooked the obvious on that one.

EDIT: I didn't mean zero on the ball joint. I meant if the angle finder was placed on a perfect horizontal surface with the magnet, it would read zero. In other words, it will read 0 in one direction and 90 in the other if placed on a perfectly level surface.
 
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theprez

New member
After my small lift (2.5") I had some pretty bad road wander/pulling. Installed lower adjustable control arms and then got it aligned. Drives much better but like mentioned in my other post my caster is a bit high.... apparently within limits tho (for stock gears/driveshaft)
 
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