Just installed the PR44u and have some spring bow on the passenger side. I measured the spring perch on both sides and they are even. Lower control arms are both even.

Would this be fixed with adjustable upper control arms? Running RK adjustable lowers at the proper length. It drives perfectly fine, just looking for a little help...headed to the rubicon in early May! This has got to be functional.


Passenger side - rearward bow



Drivers side - straight

 

Is end of the spring sitting in the pocket as it should (and seated correctly at top)?

I would start by removing both front tires and place a level against the center of top and bottom perches, both sides. I can't imagine you'll find them in line of eachother on the side that's bowing. Likely rotated aft on the lower perch. Then you'll have to determine why; perch placement on axle, CAs truly even~caster reading l-r, etc.

 

I agree. Doesn't look seated properly at the bottom.

 

Check what the others said. Then double check control arm lengths. If all that checks out, find a level surface and check the angle of the coil perches. There was a thread on JK Owners where someone with a new PR44 had similar issues and turned out the guy welding that day didn't have his V8. He had to send the axle back and they put new perches on in the correct location.

 

I'll check and report back. Thx guys

 

Looks like everything is seated

 

 

Check my above measurements. Either you have different lengths in your control arms or the guy welding the perches on was drunk.

 

Second this. My first guess would be the control arm length though.

 

Ditto. With aftermarket housings the often questionable control arm lengths provided by some kit mfrs can be even more inaccurate. Best thing to do is to determine your optimum axle position yourself. Get it up in the air (jack stands, etc.), support the axle on both ends with floor jacks, pull the wheels, shocks & springs. Remove the upper bump stop snubber. Lift the axle up slowly and evenly on both sides and center the lower bump stop extensions with the upper bump stop tubes. Use the lower arm flex joint adjustments to move the axle fore or aft. Afer you get an idea of the centering points on each side, adjust the arms to the same length on each side. (Some mfrs suggest staggering the passenger arm a bit longer than the driver.) if necessary adjust the uppers fore or aft to allow the lowers to align, you'll reset your caster with the uppers later. Put it all back together and dial in your front caster & pinion angle with the uppers. Axle should be properly centerd and the spring bow should be gone.