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Something's not right with rear lower control arms

mpv99tj

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May 4, 2021
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So I finally got my new rear lower control arms (Core 4x4 Tier 1) to replace my worn out stock ones. Adjusted them to 16", I have a 3.25 inch lift. Drivers side lower went in with no problem. Pulled out the passenger side lower and left it overnight. this evening I went to install it and it was way off, I figured it moved some over night. I had to crank it up off the ground several inches from the back of the axle at the shock mount to get it lined up. after lowering it down the passenger side is about 1.5 inches lower than the drivers. If I drive it will it settle down? TIA
 

pagrey

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You have to tighten the control arm bolts at ride height so the bushings don't have any pre-load. First thing I might do is loosen all the bolts with the Jeep on the ground and bounce it a few times then torque them back up.
 
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mpv99tj

mpv99tj

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May 4, 2021
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Central Kentucky
You have to tighten the control arm bolts at ride height so the bushings don't have any pre-load. First thing I might do is loosen all the bolts with the Jeep on the ground and bounce it a few times then torque them back up.
It was on my 4 post lift the entire time at ride height. It sat overnight with no passenger side control arm was the only difference from the drives side.
 
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freedom_in_4low

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It's probably bound up. Due to manufacturing tolerances the arm lengths aren't always equal, and tbahd ok. You want to put a jack under your rear pinion, jack it up until the first control arm you installed is unloaded so you can pull the bolt on and out, and then set the other arm to whatever length allows you to insert that bolt. Then remove the jack and tighten the bolts.
 

pagrey

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Have you measured your pinion angle? I might start there, that's kinda the purpose of adjustable arms. Vibes? Lift issues aside you do need the arms the correct length for the pinion angle and centering the axle. The lift part should work itself out if the other stuff is correct.
 
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mpv99tj

mpv99tj

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May 4, 2021
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Central Kentucky
Have you measured your pinion angle? I might start there, that's kinda the purpose of adjustable arms. Vibes? Lift issues aside you do need the arms the correct length for the pinion angle and centering the axle. The lift part should work itself out if the other stuff is correct.
Pinion angel is set, new sye installed by local shop all was fin until I installed new control arms.
 
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mpv99tj

mpv99tj

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May 4, 2021
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Just took it out for a ride and it seemed to ride fine, on the road. Took some measurements I should have taken some before but really didn't think I needed to. Right side (Passenger) is 1" lower than left (Drivers). Tire to tire on both sides it @60 1/2 inches. Lower control arms the same at about 16 1/8". Do I even have a problem? Pinion angle was not upset from original settings and is correct. Comments?
 

WallyWest

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Nov 6, 2019
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Just took it out for a ride and it seemed to ride fine, on the road. Took some measurements I should have taken some before but really didn't think I needed to. Right side (Passenger) is 1" lower than left (Drivers). Tire to tire on both sides it @60 1/2 inches. Lower control arms the same at about 16 1/8". Do I even have a problem? Pinion angle was not upset from original settings and is correct. Comments?

How old are the springs? Passenger rear is where you will start to sag first, due to engine torque loading that side more under acceleration.

Impossible to say if this is a new thing or not since you don't have before and after measurements. If your control arms are the same length as stock and your pinion is the same as before then I don't think the new arms could be causing any issues.
 
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mpv99tj

mpv99tj

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May 4, 2021
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How old are the springs? Passenger rear is where you will start to sag first, due to engine torque loading that side more under acceleration.

Impossible to say if this is a new thing or not since you don't have before and after measurements. If your control arms are the same length as stock and your pinion is the same as before then I don't think the new arms could be causing any issues.
New list within the last couple of months
 

freedom_in_4low

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What is more important: Equal length or free moving?
Free moving.

Stock arms allow for some difference because they have soft rubber bushings and they're flexible stamped sheet metal. Adjustable arms are heavy tubes with stiff bushings so they need to be set to avoid bind.
 

cpwolf

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Pinion angel is set, new sye installed by local shop all was fin until I installed new control arms.
Just curious, you’re saying you got a new SYE installed, and still kept the factory CA’s, and set new CAs to same distance.

Are you not going to change the pinion angle with a SYE installed? Or is that just coming?

You’re measuring the perches, for the height there, correct?

I would take the advice, have sitting on ground, loosen the CAs, Sway Bar, Track bar. Bounce it and measure the springs.
 

cpwolf

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AND don't forget to retighten the CAs while it's still sitting on fairly flat/level ground.
Agree, should have spelled that out.

For me, all CA work is sitting on the ground.
I replaced all 4 with Savvy Double Adjustable. Sitting on ride weight. I did is a ratchet strap to the frame some, because I could reach it and the bolts.

You can also have a 2nd person on a jack on the pinion for subtle or have that person room tire forward etc for bolt adjustments.

Either way I don’t believe you need to use anything else. And you should have it straight on the ground ride weight and tighten the bolts all then. That’s what I’ve learned here, and from my other experiences, and it should be pretty set up unless something is done wrong.
 
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