Alignment issues/questions

Hey all. I have a 2000 XJ lifted about 3.5 inches in front and 4 inches in the rear with adjustable LCAs and track bar from IRO. I recently replaced the unit bearings and had some odd vibrations at speed, so I took it to a free alignment check place and had it looked at. The ball joints feel solid with the jeep jacked up and pushing/pulling on the wheel and pressing up on it with a pipe. Tie rod ends and draglink/TRE are all new as well.

The report lists:
Camber driver's side: -1.52 degrees
Passenger's side: -0.47 degrees

Caster driver's side: 7.24 degrees
passenger's side: -0.47 degrees

Pinion angle is at 5.5 degrees (my measurement off front of the diff)

Toe: driver's side: 0.97 degrees
passenger's side: -0.90 degrees
total: 0.07 degrees (in spec, my measurement is 3/16 inch)

Rear thrust angle: -0.29 degrees

1: Is it ok that my caster has that much difference between sides? When I originally set the LCAs, I set caster off the tops of the ball joints at 7 degrees. When I measure now I get almost 10 degrees passenger and 7 degrees driver. That measurement isn't as precise as an alignment machine but shouldn't they be close? The pinion angle didn't change between initial setting and now.

2: What could cause the bad camber? A bent axle? Everything seems tight.

3: Is there any way to fix the thrust angle?

4: The rear pinion seal leaks when I have the drive shaft bolted in but stops when it is taken out. Is this simply a pinion angle adjustment or possibly related to the camber being out of spec or caster differences?

Thanks for your help!

I would try to correct the castor angle. When I installed my adjustable lower control arms I simply measured with a ruler to the length I wanted.

A one degree difference in camber should not be an issue. My 01 XJ has had something similar since I bought it at 36,000 miles and was told to just rotate the tires, not worth even trying to fix it/thinking about it.

Not sure the thrust angle is a real issue

The rear pinion seal has nothing to do with your front alignment. Check for play in the bearings & replace the seal & bearings as needed.

I would suspect the shop F'd up the job. Those numbers can't be right. You need a second diagnosis/opinion before you do anything.

• Did you set the control arms equal ?
• Thrust angle really doesn't matter unless it is excessive.
• Install a new rear pinion seal.
• You probably need an SYE if you don't have one.

Thanks for the replies! The rear pinion seal is a typo, I meant front (I do have an SYE for what it's worth).

md21722: How would you suggest correcting the caster? Setting the LCAs at separate lengths doesn't do anything for a solid axle from what I understand. If the camber was just one degree difference, I wouldn't be so worried. However, the limit is -0.75 to 0.50 (per the report I got). I also have a strong right hand pull which I think is coming from that out of spec camber. Could be wrong though?

Tim_MN: The LCAs are set to equal length. I'll take it by another place in the next few days for another free alignment check. I have to finish patching rust in the floor first.

The LCA's should be the same length. I wasn't trying to suggest they be different length. I was questioning if you had set them the same length, or was going by a possible faulty angle measurement in which case no length measurement was taken. Tim may be on to something with getting a second alignment check. It's hard to believe the castor would be different with the LCA's being the same length. Do you have the factory clevis in each frame pocket and there are no shims on each side? I would forget about the camber. It's not causing your pull or affecting your castor to any significant amount, especially not 7 degrees. If the front pinion seal is leaking, its the same story as the rear. Make sure the pinion isn't loose (from bad bearings) otherwise you have two problems and a new seal won't last long. Then change the seal.

An almost 8 degree difference in castor would mean your axle looks like a pretzel. I agree on getting a 2nd opinion.

Dammit, my proofreading is lacking. Sorry guys, that should be 6.14 degrees on passenger caster.

md21722, thanks for clarifying. Each side has the factory clevis and no shims.

For the pull try rotating your tires around and see what happens. Also make sure the brakes are sticking, etc.

The max differences are at the high end of the tolerance, but not high enough to suggest damage. Are there any problems evident from the current alignment ? The vibes are probably from the pinion angle.

Short arm lifts are a compromise. You have to balance pinion angle against caster, you want good enough pinion angle to prevent drive shaft vibes and you take whatever caster you can get. Toe-in should be about 1/16 to 1/8", more toe-in for larger tires. Camber is fixed, changes with the lift, and you can't do anything about it. Offset ball joints can address either caster or camber, pick one, and one only.

I still would have another shop check the alignment numbers, but my 2000 has not been to the alignment shop since it was lifted 12 years ago, and there have been no problems in 100,000 miles.

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