I made the mistake of off-roading and not checking the torque on my suspension components afterward, which over time wallowed out the threads on my adjustable rear upper control arms and caused a host of issues with my Jeep. With a lifted Jeep you have to make sure to check the torque on everything after abusing it. With the adjustment threads all wallowed out, under heavy acceleration, my passenger rear upper control arm (UCA) actually lengthened, torquing the rear axle slightly to the right, which makes the Jeep pull a little to the left. The lesson here is to always check that everything is tight after you go off-roading!
With all that being said, I picked up a set of adjustable rear upper control arms from SPC to replace the ones that were destroyed by my negligent maintenance. Taking them out of the box, I already like that they have an external adjustment so I won't have to disconnect them to adjust the length when I align the rear end. I like the forged ends with XAXIS flex joints, as well as the geometry of where they put the bend. It seems to give a bit more room for big tires with slightly higher offset wheels. Generally, 4.5" backspacing is an easy number to clear big tires on the JK, but mine are 4.75" which give very little clearance to the upper control arms. However, these new SPC arms are bent differently and look as though they will gain me some clearance over my current adjustable control arms.
The first task was to get the rear end on jacks and to remove the wheels. I put jack stands under the frame right in front of the lower control arm mounts and kept my floor jack under the rear pumpkin (differential) so I could cycle the suspension to check clearances. The reason to check clearances in my case is that I'm not just installing these rear UCAs, I'm also installing some other adjustable rear lower control arms (LCAs) so I can push my rear axle back just a little to center it in the wheel wells.
The next step is to set the starting lengths for the UCAs. According to the instructions, you screw it all the way together then adjust out the middle adjuster nut until it is about the same length as the stock arms. In my case, the stock upper arms are 17 7/16" from eye to eye.
How did the installation end? Check out part two for results!