Post by pentacleus on Sept 30, 2014 15:12:58 GMT -6
A little info that might help someone (some day).
History
On a 2013 Wrangler Rubicon 2 door (weighted with bumpers, winch, etc,etc), I just upgraded from 2.5 OEM (Old Man Emu) coils to 4 inch (RK) coil springs, which made me have to upgrade to new adjustable control arms. In this post, I am specifically speaking of the rear control arms. I chose Rock Krawler since I had had previous experience with them, and had had great success with them.
Observations
I received the adjustable lower control arms with expectations to push the rear axle back and then set the camber with the new adjustable upper control arms. Let me tell you, these new RK CA's are beefy and bad ass. I like. What I didn't know at time of purchase that is a bit of a problem is that the "adjustable" part of this control arm has a shortest setting that is 1" longer than OEM. Therefore, you can not set them to the OEM length.
Off topic, but worth noting: I had OME 2.5" rear coil springs, and I always thought they were really big 2.5" springs. When I installed my 4" RK coil springs, I thought it looked like the wrangler set lower in the rear. I hadn't measured height before/after spring swap so i had no way to verify. So I measured and then swapped out again, putting the 2.5 OME springs on. The jeep now sits 1" high with the 2.5 OME than with the 4" RK springs. Needless to say, the 2.5" OME springs stayed on the rear. On the other end of the vehicle, the 4" RK front springs definitely lifted the front. Wrangler is level. I will be adding 1" to rear in the form of a spacer b/c I want the Jeep level when loaded with gear.
Back to the story
Since I had Old Man Emu rear coils (which have a large diameter coil), even at the RK Lower CA's shortest setting, the axle pushed my OME coil springs into the rear track bar on the passenger side (high side of the trackbar). It's not barely touching, it is smashed into it. This would not be a problem if I had smaller diameter coil springs like the 4" RK's that I had just taken off.
Also, because I had to add camber by extending the upper control arms, my rear coil springs are now bowed back. The angle on the coil perch (the flat piece welded on the axle that the coil springs sit on) has to fixed. I hope by fixing this angle that my coil is no longer touching my track bar
How to fix
Option 1 - I've done my internet research across all the Wrangler boards and I have a few options. Rock Krawler makes "Rear coil spring correction wedges". This basically sits on the axle perch below the springs and corrects the angle. I am hoping this works as I just ordered a set for $24. I'm curious if I get a little lift out of this poly wedge (aka spacer)
Option 2 - JKS Adjustable Spring Mounts Wrangler JK #2400. This requires you to break the welds of the existing lower spring mount (aka perch) (welded to axle) then clamp with u-bolt, these new spring mounts onto the axle. Seems like a good solution to me but haven't seen anyone with a bolt on perch.
Option 3 - Take off existing lower coil mount (same as option 2) and re-weld it onto the axle in the right place. Cheap and good, but not adjustable. Also takes longer than just bolting on adjustable perch as in option 2.
Option 4 - Modify the Lower CA's making them shorter. There is one guy who has had good luck cutting his lower CA's in half, removing 1/2 inch of metal and then welding them back together. I think it would be better to shorten the CA piping at the adjustable end. You would have to ensure that you did not mess up the threaded pipe though. Since I'd have to take 1/2" off the pipe and 1/2" inch off the heim join that screws in, I think I would cut through both at the same time (threaded together 1" and cut at the 1/2" mark on the pipe) to ensure I didn't mess up threads.
Conclusion (thus far)
I opted for option 1 (angle adjustment wedge from RK). We'll see if the wedge has an acceptable angle. If not then I will probably go with option 4 and shorted the CA by 1/2".
Maybe this will be helpful to someone. I did find it amazing that the RK lower control arms could not be adjusted to OEM specs and I'm even more amazed that the 4" RK rear coil springs (RK02002) are shorter than my 2.5" OME coil springs.
Josh
History
On a 2013 Wrangler Rubicon 2 door (weighted with bumpers, winch, etc,etc), I just upgraded from 2.5 OEM (Old Man Emu) coils to 4 inch (RK) coil springs, which made me have to upgrade to new adjustable control arms. In this post, I am specifically speaking of the rear control arms. I chose Rock Krawler since I had had previous experience with them, and had had great success with them.
Observations
I received the adjustable lower control arms with expectations to push the rear axle back and then set the camber with the new adjustable upper control arms. Let me tell you, these new RK CA's are beefy and bad ass. I like. What I didn't know at time of purchase that is a bit of a problem is that the "adjustable" part of this control arm has a shortest setting that is 1" longer than OEM. Therefore, you can not set them to the OEM length.
Off topic, but worth noting: I had OME 2.5" rear coil springs, and I always thought they were really big 2.5" springs. When I installed my 4" RK coil springs, I thought it looked like the wrangler set lower in the rear. I hadn't measured height before/after spring swap so i had no way to verify. So I measured and then swapped out again, putting the 2.5 OME springs on. The jeep now sits 1" high with the 2.5 OME than with the 4" RK springs. Needless to say, the 2.5" OME springs stayed on the rear. On the other end of the vehicle, the 4" RK front springs definitely lifted the front. Wrangler is level. I will be adding 1" to rear in the form of a spacer b/c I want the Jeep level when loaded with gear.
Back to the story
Since I had Old Man Emu rear coils (which have a large diameter coil), even at the RK Lower CA's shortest setting, the axle pushed my OME coil springs into the rear track bar on the passenger side (high side of the trackbar). It's not barely touching, it is smashed into it. This would not be a problem if I had smaller diameter coil springs like the 4" RK's that I had just taken off.
Also, because I had to add camber by extending the upper control arms, my rear coil springs are now bowed back. The angle on the coil perch (the flat piece welded on the axle that the coil springs sit on) has to fixed. I hope by fixing this angle that my coil is no longer touching my track bar
How to fix
Option 1 - I've done my internet research across all the Wrangler boards and I have a few options. Rock Krawler makes "Rear coil spring correction wedges". This basically sits on the axle perch below the springs and corrects the angle. I am hoping this works as I just ordered a set for $24. I'm curious if I get a little lift out of this poly wedge (aka spacer)
Option 2 - JKS Adjustable Spring Mounts Wrangler JK #2400. This requires you to break the welds of the existing lower spring mount (aka perch) (welded to axle) then clamp with u-bolt, these new spring mounts onto the axle. Seems like a good solution to me but haven't seen anyone with a bolt on perch.
Option 3 - Take off existing lower coil mount (same as option 2) and re-weld it onto the axle in the right place. Cheap and good, but not adjustable. Also takes longer than just bolting on adjustable perch as in option 2.
Option 4 - Modify the Lower CA's making them shorter. There is one guy who has had good luck cutting his lower CA's in half, removing 1/2 inch of metal and then welding them back together. I think it would be better to shorten the CA piping at the adjustable end. You would have to ensure that you did not mess up the threaded pipe though. Since I'd have to take 1/2" off the pipe and 1/2" inch off the heim join that screws in, I think I would cut through both at the same time (threaded together 1" and cut at the 1/2" mark on the pipe) to ensure I didn't mess up threads.
Conclusion (thus far)
I opted for option 1 (angle adjustment wedge from RK). We'll see if the wedge has an acceptable angle. If not then I will probably go with option 4 and shorted the CA by 1/2".
Maybe this will be helpful to someone. I did find it amazing that the RK lower control arms could not be adjusted to OEM specs and I'm even more amazed that the 4" RK rear coil springs (RK02002) are shorter than my 2.5" OME coil springs.
Josh
Just remember...we give them back in 10 months 
It's alive!! 
