• Want to add an app icon for this forum to your mobile device's home screen? Check out this thread to see how.
  • Have an event you want to share? Check out the new forum event calendar and how-to use it in this thread here.
  • To both new members and existing members, please read this thread about posting your topics in the correct sub-forum. It makes my job (and my life) a lot easier!

Issues with installing rear control arms and setting pinion angle

Napalmsundae

New Member
Jul 7, 2019
4
Florida
I am installing the rubicon express 3.5" lift with monotube shocks on my 1999 Sahara. I'm having issues installing the rear control arms and setting the Pinion angle. It looks as though the arms ar too short and the spring mounts are at an odd angle.
104091
The installation procedures are a little confusing when it comes to setting the innicial lower control arm length.
104092

It says set the innicial length at 32 5/8", and goes on to state that the measurement should be 42.6". I have it set at 32 5/8 now. And it looks way too short. We are going to see how far we can extend these arms, but in the directions it does say final length should be '32 5/8 - 33.25 depending on lift'
 

Chris

Administrator
Staff Member
Sep 28, 2015
38,757
Salem, Oregon
It looks like all you have to do is slightly tilt the axle back and the top arms should bolt right in. The angle doesn’t matter as those joints have a lot of movement in them.

Don’t pay attention to the numbers, they are irrelevant. What matters is the bottom control arms are adjusted to the point where your upper joined bumper is perfectly center with the spring perch below it.

The uppers will then be used to dial in pinion angle. Any numbers they give you in the instructions for measurements of control arm lengths should only be used as rough estimates as there is no way they can be 100% accurate.
 

bobthetj03

vibrajeep
Supporting Member
Ride of the Month Winner
Feb 3, 2017
9,160
NorCal
What Chis said. Jack the axle to full bump and adjust lowers so the jounce bumper sits as close to center of lower spring perch as you can, then use the uppers to set pinion angle.