99xjlove

I was just noticing that my front pinion isn't pointed up at all with my new LA kit. I think it is creating some driveline vibes. I never had any before and I'm seeming to get some. What way should I go about handling this. I Had it aligned and they didn't say anything about adjusting my UCA lengths so I have them at what RE recommended.

BlueXJ

Are the RE UCAs adjustable? If so then lengthen them until they point your pinion towards the transfer case. I have never heard of front driveshaft vibrations with a RE kit under 6" but each Cherokee is different.

SeriousOffroad

Take it back in and have the measure the caster. It should be 6-8 degrees. Adjusting the caster to those numbers will insure proper Return to Center and correct your pinion angle at the same time.

muddeprived

Most alignment shops won't touch caster, even if you have adjustables. Ask me how i know. Go back and see if they will do it, if not get an angle finder and measure/adjust.

99xjlove

I think that is what I'm going to do. Is there a write up on it somewhere? I know that if I just adjust my UCA's out then it will raise my pinion angle. But I don't want to throw off the Caster.

Here is a couple of pics showing the angles of the DS and pinion. They arent that extreme but it seems to be giving me problems.

muddeprived

That's pretty obvious. You can take off the front shaft for the time being until you adjust it. Save the joint.

SeriousOffroad

The most accurate way is to put your anglefinder in the machined flat portion of the inner C, but since you probably don't want to diassemble your axle to do that...

http://go.jeep-xj.info/HowtoAlignment.htm

dabeast727

omg thats a really bad angle haha wow

99xjlove

Those are the specific lengths that RE gave in the instructions for my lift. I only did what they said. If I lengthen the UCA's how far should I go? I read the go jeep info but i'm kinda clueless without step by step pics.

muddeprived

If you can't figure it out, do it the redneck way. Lengthen the upper arms 1/4". Test drive it. If steering still feels alright and vibes are lessened or eliminated, call it a day. If you need more, lengthen them 1/8" (a.k.a. two turns) more and keep doing 1/8" it till it's right. Focus on the steering mostly because you'll start to notice it changing a little bit everytime you adjust the caster. You won't crash and burn if your caster is a little off so don't be nervous. You will notice change in the return-to-center with the steering as you adjust and maybe get touchy or not. This is all based on my experience on the TJ. I knew how the steering handled and what i wanted so i adjusted the caster this way and had a shop print a read-out on the angles and i was in the ballpark of what was acceptable caster. I got lucky or i just knew the jeep very well.

If you don't feel right doing this, have a shop do it for you.

99xjlove

I can handle doing that I just didn't want to throw everything out of wack. I plan on doing ball joints here soon but untill I do those I don't really want to mess with it too much. But now that I see that angle I know I need to fix it.

99xjlove

Okay I ended up taking the UCA's from 15 3/4" to 16 1/4". That 1/2" got rid of the driveline vibes. I'm still gettting some vibes when I hit the brakes though. Also in the mornings when I back out I hear a weird knid of rubbing noise. This is leading me to believe that my Wheel bearings are going out. What is an okay brand to buy? Good quality with a fair price?

BlueXJ

Mine came from NAPA and I have had no problrms in the 3 years since they were replaced.

okcjeeper

Yeah NAPA or look for TIMKEN unit bearing assemblies..

muddeprived

napa

If that's not available, rockauto has them for $73.