SPC Control Arms For Jeep JK: Part Two

Now that the old damaged upper control arms are removed, it's time to set the length, install them, adjust them, put the wheels back on and then tighten them.

In part 1, the instructions said to screw in the rod end and adjust the sleeve out to the length of the stock UCAs (upper control arms) as a starting point for installation. My stock UCAs were 17 7/16" from eye to eye, but I was also doing adjustable lower control arms and I wanted to locate my axle closer to the center of the wheel wells - about 1/2 inch or so back from where it was, so my starting point was a bit different. I took the SPC UCA and held both ends stationary then rotated the adjustment sleeve exactly eight full turns, which put them at 17 3/4" eye to eye as my starting point. I adjusted out a little longer for pinion angle, and that length is working out very well so far and doesn't cause any interference between the springs and the sway bar or track bar, so I left it at that length.

I inserted the frame side end (the end with the rubber bushing) and lined up the flag nut with the bolt first since that one is the hardest to get threaded blindly up in the frame. Once that one was in, I moved to the axle side. This one, of course, doesn't just slide in nicely since I'm changing the lengths, therefore it took some wrestling around to get the holes to line up. If you use ratchet straps cleverly, you can torque the axle enough to line the holes up, otherwise you'll probably need a second person to help out.

Once the uppers were in, the next step was to install the lowers, which were set to 20.25" eye to eye. Again, my pinion is a little high for my liking (approximately five degrees), but it's streetable now. All I have to do to get it back to off-road-ready is lengthen the uppers just a little more and make sure there are no clearance issues. That's a job for another day!

After everything was bolted in place (and I can't reiterate this enough) loosely, I put the wheels back on and set the Jeep on the ground. The jack and jack stands were used to test the clearance by cycling the suspension. This means basically flexing the axle up into the wheel well on one side at a time and making sure that all components move freely.

Once the Jeep was holding its own weight, I torqued all eight control arm bolts and the adjustment locking jam nuts. If you're only installing upper control arms, it's recommended to loosen the bolts on the lower arms too, to take out any bind in them that might be caused by installing different length upper arms.

The torque specs for the control arms I used are as follows:

Lower Control Arm Frame Side: 130 ft lbs

Lower Control Arm Axle Side: 85 ft lbs

Upper Control Arm Both Sides: 55 ft lbs

I have had these on for over a month and they are still working great! With the XAXIS Flex joints in these uppers and the johnny joints in my lowers, the whole rear end moves up and down much nicer than it did before, and I haven't noticed any change in ride quality!

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