Replacing upper and lower control arms on a '96 XJ
 

I'm about to replace both the upper and lower front control arms on my XJ and was wondering if there was any advice before I got started. Far as I can tell I just need to take a couple days spraying some PB on the bolts before I do the job and then just yank em out and put the new ones in.

Any advice maybe?

Spraying the bolts in advance will indeed help. The lowers are very straight forward to replace. The tops are easy if you are not changing the axle mounted bushings. If you intend to replace them as well, the job can be a little more involved because they can be difficult to get to with enough power to get the pressed in/out. Are you planning on doing those bushings? (I have been putting off my uppers for this reason, because I don't think it is worth doing the arms if I'm not going to do the bushings as well).

Key advice. Only work on one arm at a time, or the axle will move on you and make it surprisingly difficult to line up the holes when it is time to put the bolts back through.

Even when doing one at a time, my second one was difficult to get lined back up because the axle had shifted just slightly. I was able to get the holes lined back up by using a long steel punch as a type of lever. However, I think I would have encountered less hassle if I had just thoroughly chocked both front wheels, and -not- lifted the front end (which is ok for the lowers but usually uppers require some space between the axle and the vehicle).

If I was to do it again, I would have used ramps (for working room underneath) and chocked the wheels on the ramps to help reduce any movement of the axle.

Regardless, the job was straight forward. Its bolts, and large chunks of steel. Very little finesse. You may want to have some rubber safe lubricant (non-petroleum based) on hand for lubing any bushings before installing, otherwise they will possibly squeak and squeal. (A can of Fluid Film would work - it is safe for rubber/plastic).

Are you replacing the upper axle bushings? If not, you might as well since youll have it torn apart. They can be a PITA as they are pressed into the axle. A balljoint press will work. Same deal, press out the old and press in the new. Replace one arm at a time. That will help keep the holes lined up. When replacing suspension parts i like to replace the hardware as well, but thats up to you.

Chock the rear and/or set the parking brake beforehand, and get an alignment after.

Hopefully you don't have to, but be ready to have to cut the bolts if they get stuck in the bushings. PITA cutting hardened bolts. I used a Sawzall with the Milwaukee metal cutting blades - like 2 per bolt.

Like Jordan said, do one at a time or the axle will roll on you and getting the holes lined up again will be more difficult.

Get the control arms with the bushings installed already, and do the bushings on the axle side too, like fb97 said. Make sure you secure the jack stands right, so the Jeep doesn't fall on you. There is a lot of pushing and pulling and cursing with this job.

Thanks for all the advice.

But crap, yeah I forgot the top control arms involved pressing that bushing out. Yeah I guess if I'm doing it I better go ahead and get that bushing out too.

Someone was strongly suggesting I get adjustable control arms. Is there a big advantage to these?

I did mine one at a time just sitting on the ground. I parked behind another Cherokee and ratchet strapped the font axle to that ones rear axle. The a le still moved alittle but wasn't too hard to get back into place.
I had to pull the axle forward until the two nuts on the backs of the LCA brackets were against the bracket before I tightened the control arm bolt.

Adjustable lower control arms are used to maintain a proper caster angle at the steering knuckle when a suspension lift has been fitted on the vehicle. Usually, this is not necessary unless the lift is greater than 2" (though some folks may recommend it ealier). I have about 1.5" lift on the front, with stock control arms, and do not have any steering/alignment issues. Do you currently have a lift? Are you planning on adding one soon? If so, then it is a consideration.