Rear Axle Adjustments
03-10-2020, 05:36 AM
#1
JK Enthusiast
Thread Starter
Rear Axle Adjustments
Looking at adding rear adjustable control arms so I can properly align the rear axle forward and aft. Is there a specification? What are good measuring points under the Jeep?
The Jeep is sitting on a 2.5 AEV lift with 3.5in up front. I have upper and lower adjustable control arms up for proper axle alignment, but I can see that the rear axle favors forward just a tad.
The Jeep is sitting on a 2.5 AEV lift with 3.5in up front. I have upper and lower adjustable control arms up for proper axle alignment, but I can see that the rear axle favors forward just a tad.
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jadmt (03-10-2020)
03-10-2020, 07:45 AM
#4
JK Jedi
That I am.
Well there is the stated wheel base if you want to call that a spec but if you don't have the front axle position correctly that won't work. Center of front axle to center of rear axle is the best way to measure, I would check the front to make sure its right before removing the factory arms. Length of arms will change with height, the higher you are the longer they need to be. If you are running factory axles set your pinion straight to the output shaft, if you have aftermarket double cardone shafts then it should be a couple degrees down from straight at the pinion.
I can't wait to see the review/install video of the rear arms install with all the pertinent info.
Well there is the stated wheel base if you want to call that a spec but if you don't have the front axle position correctly that won't work. Center of front axle to center of rear axle is the best way to measure, I would check the front to make sure its right before removing the factory arms. Length of arms will change with height, the higher you are the longer they need to be. If you are running factory axles set your pinion straight to the output shaft, if you have aftermarket double cardone shafts then it should be a couple degrees down from straight at the pinion.
I can't wait to see the review/install video of the rear arms install with all the pertinent info.
The following users liked this post:
ballistik_monkey (03-10-2020)
03-10-2020, 08:00 AM
#5
JK Enthusiast
Thread Starter
That I am.
Well there is the stated wheel base if you want to call that a spec but if you don't have the front axle position correctly that won't work. Center of front axle to center of rear axle is the best way to measure, I would check the front to make sure its right before removing the factory arms. Length of arms will change with height, the higher you are the longer they need to be. If you are running factory axles set your pinion straight to the output shaft, if you have aftermarket double cardone shafts then it should be a couple degrees down from straight at the pinion.
I can't wait to see the review/install video of the rear arms install with all the pertinent info.
Well there is the stated wheel base if you want to call that a spec but if you don't have the front axle position correctly that won't work. Center of front axle to center of rear axle is the best way to measure, I would check the front to make sure its right before removing the factory arms. Length of arms will change with height, the higher you are the longer they need to be. If you are running factory axles set your pinion straight to the output shaft, if you have aftermarket double cardone shafts then it should be a couple degrees down from straight at the pinion.
I can't wait to see the review/install video of the rear arms install with all the pertinent info.
With my basic understanding of pinion angles, when using a CV Double Cardan shaft the pinion flange/yoke should be inline with the driveshaft. You mentioned it should be "down" which is how the oem shaft should be if I'm not mistaken, but I'm not an expert on this subject.
Last edited by Dirt Hammer; 03-10-2020 at 08:09 AM.
03-10-2020, 08:17 AM
#6
JK Jedi
On the front both would be down and that is due to caster adjustment when lifted. When you accelerate the rear axle will rotate slightly up, this puts the driveshaft straight at the pinion when it has the greatest amount of force on it. You don't have to put the slight angle in if you don't want to, just my recommendation.
On a 2 joint driveshaft you should match the angles on the top and bottom U joint.
On a factory CV (Rzeppa) joint the angle does not have to be matched with the pinion u-joint and can be placed straight to the output for max clearance at the pinion for obstacles. If you want angle at the pinion then go for it.
On a 2 joint driveshaft you should match the angles on the top and bottom U joint.
On a factory CV (Rzeppa) joint the angle does not have to be matched with the pinion u-joint and can be placed straight to the output for max clearance at the pinion for obstacles. If you want angle at the pinion then go for it.
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03-10-2020, 09:51 AM
#8
JK Enthusiast
Thread Starter
On the front both would be down and that is due to caster adjustment when lifted. When you accelerate the rear axle will rotate slightly up, this puts the driveshaft straight at the pinion when it has the greatest amount of force on it. You don't have to put the slight angle in if you don't want to, just my recommendation.
On a 2 joint driveshaft you should match the angles on the top and bottom U joint.
On a factory CV (Rzeppa) joint the angle does not have to be matched with the pinion u-joint and can be placed straight to the output for max clearance at the pinion for obstacles. If you want angle at the pinion then go for it.
On a 2 joint driveshaft you should match the angles on the top and bottom U joint.
On a factory CV (Rzeppa) joint the angle does not have to be matched with the pinion u-joint and can be placed straight to the output for max clearance at the pinion for obstacles. If you want angle at the pinion then go for it.