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Unread 01-16-2012, 10:33 AM   #1
scot68
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Problems centering rear axle during lift install!

I am in the process of installing a Savvy 4” lift with Aluminum arms, adjustable rear TB and a Ford 8.8 axle. Everything has gone together as it should until I tried to center the rear axle. After installing the rear arms and springs I set the Jeep’s weight down on the axle and bounced it a few times then took my axle side to side measurements. Using two 24” pieces of Alum. square stock I clamped them vertically to the axle flanges and measured to the frame on each side. Initially the axle was offset 11/16” to the passenger side so I used a heavy duty ratchet strap to draw the axle over to center. It took a huge amount of effort on the strap to get the axle to move but once it was centered I adjusted and installed the TB. When I released the strap I noticed the jeep is now leaning a couple inches lower on the rear pass side (it sat level before I centered the axle). When I disconnect the TB the Jeep sits level. I know a lot of TJ’s exhibit a lean to some degree however this is pretty bad and the fact that it sits level without the TB connected has me stumped. None of the frame brackets appear to be bent and the axle was just set up by ECGS so I don’t think it is the problem. I have searched and found a lot of threads regarding leaning but haven’t found any with this scenario. Any suggestions would be greatly appreciated.

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Unread 01-16-2012, 10:39 AM   #2
little_Jeep
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Photos sure would be nice..... The axle doesn't have to be exact.. as long as the axle is straight (square) under the Jeep, it will track fine, even if the axle is not perfectly centered under the Jeep. With the 8.8, the pumpkin is not on center, so you have to measure wheels to frame, or wheels to tub. Like I said, you just need it to be ballpark close, not perfect.
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Unread 01-16-2012, 10:42 AM   #3
AJeep
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First I have to say Im jealous. I am saving for a Savvy lift. My lift came with a rear track bar bracket. It lifted the track bar and allowed for the axle rotation by 10* I believe it is. But its a cheap lift, but I do not have any lean at all.
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Unread 01-16-2012, 10:46 AM   #4
vosevichs
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Are your springs straight when the axle is centered? I'd double check your measurements. Check the mount locations on the axle.
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Unread 01-16-2012, 11:24 AM   #5
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Quote:
Originally Posted by little_Jeep View Post
Photos sure would be nice..... The axle doesn't have to be exact.. as long as the axle is straight (square) under the Jeep, it will track fine, even if the axle is not perfectly centered under the Jeep. With the 8.8, the pumpkin is not on center, so you have to measure wheels to frame, or wheels to tub. Like I said, you just need it to be ballpark close, not perfect.
Yes the 8.8 pumpkin is offset 2" to the pass side however with the additional 11/16" now it is almost offset by 3". With that much offset I'm wondering about increased u-joint wear and I don't want the Jeep to "dog-track" down the road.
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Unread 01-16-2012, 11:29 AM   #6
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Quote:
Originally Posted by vosevichs View Post
Are your springs straight when the axle is centered? I'd double check your measurements. Check the mount locations on the axle.
The centering "pin" on the axle spring perch is considerably smaller then the ID of the spring so I can get the springs centered. I will take some more measurements and some photos tonight.
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Unread 01-16-2012, 11:38 AM   #7
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Please post a picture of both sides of the axle...with measurements.
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Unread 01-16-2012, 12:03 PM   #8
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The easiest way that I've found is waiting until you've got everything bolted up, tires on, sitting on flat ground. Measure, determine the discrepancy and to which side it needs to go, unbolt the axle end of the track bar, and adjust it to the correct length. Then, have someone else lean or push on the body in the correct direction until you're able to slide the track bar into the mount and slide the bolt through the sleeve. Measure again and repeat if necessary. THEN square up the axle and position it correctly (including pinion angle). It's easiest to do all of that with the rig sitting on the tires.
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Unread 01-16-2012, 12:49 PM   #9
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Originally Posted by Imped View Post
The easiest way that I've found is waiting until you've got everything bolted up, tires on, sitting on flat ground. Measure, determine the discrepancy and to which side it needs to go, unbolt the axle end of the track bar, and adjust it to the correct length. Then, have someone else lean or push on the body in the correct direction until you're able to slide the track bar into the mount and slide the bolt through the sleeve. Measure again and repeat if necessary. THEN square up the axle and position it correctly (including pinion angle). It's easiest to do all of that with the rig sitting on the tires.
That's basically what I have done, everything is bolted up aside from installing the tires. I have the weight on the axle and the axle is supported with jack stands at ride height. There is no way someone could push and move the tub, with a heavy duty ratchet strap I use for cinching cars down on my car hauler I had a hell of a time getting the axle to move the needed 11/16 to the driver's side. Using my feet I could barley crank the ratchet. The axle will eventually move the needed amount to center however there is so much tension that the track bar is sucking down the pass side of the jeep a couple inches! Unbolt the TB and it sits level but the axle is off center again..
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Unread 01-16-2012, 03:12 PM   #10
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Take out one end of one of the UCAs. Pull your axle over to center then adjust the CA to line up with the bolt hole, then bolt it back in...
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Unread 01-16-2012, 03:30 PM   #11
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Your pushing & pulling on the control arms causing pressure on the spring and control arms. Center the axle with the control arms where there is no bind in the control arms.
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Unread 01-17-2012, 08:06 AM   #12
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I am a little curious if this could be my problem as well so I will be watching this thread. I installed the Savvy 3" lift this summer and have had a .75" lean to the passenger side ever since installing the lift.
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Unread 01-17-2012, 09:18 AM   #13
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Quote:
Originally Posted by srfnfly227 View Post
I am a little curious if this could be my problem as well so I will be watching this thread. I installed the Savvy 3" lift this summer and have had a .75" lean to the passenger side ever since installing the lift.
ALWAYS set pinion angle and center the axle with ONLY 1 upper installed.

Do not take that to mean that the upper is for only setting pinion angle. If you set the pinion angle and in the process move the axle too far forward or back in the opening, adjust the lowers to fix it.

Set the frame level with the weight of the rig on the axle and the axle level and one upper installed. Adjust the trackbar, install it, check for center, adjust as needed.

Only when all the adjustments and centering are done then go ahead and install the last upper.

With a floorjack or similar, tip the axle until you can spin the bolt in the first upper by hand which lets you know there is no pressure or preload on the bolt.

Install the second upper by adjusting it to the length that lets you slip the bolt in. This will prevent any bind or unequal loading of the control arms.

There is simply no reason to attempt to set uppers any other way. You have no way to know, find out, or even care that the mounts are in EXACTLY the same spot, so you adjust the arms to fit what is there, not what you think is there.
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Unread 01-17-2012, 09:19 AM   #14
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Quote:
Originally Posted by srfnfly227 View Post
I am a little curious if this could be my problem as well so I will be watching this thread. I installed the Savvy 3" lift this summer and have had a .75" lean to the passenger side ever since installing the lift.
How did you set the length of your uppers?
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Unread 01-17-2012, 10:48 PM   #15
scot68
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Quote:
Originally Posted by mrblaine View Post
ALWAYS set pinion angle and center the axle with ONLY 1 upper installed.

Do not take that to mean that the upper is for only setting pinion angle. If you set the pinion angle and in the process move the axle too far forward or back in the opening, adjust the lowers to fix it.

Set the frame level with the weight of the rig on the axle and the axle level and one upper installed. Adjust the trackbar, install it, check for center, adjust as needed.

Only when all the adjustments and centering are done then go ahead and install the last upper.

With a floorjack or similar, tip the axle until you can spin the bolt in the first upper by hand which lets you know there is no pressure or preload on the bolt.

Install the second upper by adjusting it to the length that lets you slip the bolt in. This will prevent any bind or unequal loading of the control arms.

There is simply no reason to attempt to set uppers any other way. You have no way to know, find out, or even care that the mounts are in EXACTLY the same spot, so you adjust the arms to fit what is there, not what you think is there.
Thank you to those that replied above especially MrBlaine! Once I disconnected one upper arm I was able to easily center the axle, set the pinion angle and connect the track bar without the Jeep leaning.
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