What is a Rear Control Arm?
A Rear Control Arm and What It Does
There are upper and lower control arms on most live axle vehicles. The easiest way to think about control arms and what they do is to understand that they connect to the vehicle’s chassis to help stabilize movement. Simply put, the control arms keep the vehicle and the wheels aligned and moving in unison.
Rear Control Arms
The rear control arms limit the back-end movement of the vehicle to keep it from shifting back and forth in the chassis. At the same time, the lower control arms help put the power to the ground by positioning the axle properly in relation to the chassis.
The job of the upper control arms is to retain the driveshaft pinion angle. If the driveshaft pinion angle is not maintained accurately, the axle's rotation will not be centered, which shortens the life of the universal joint in your car.
Adjustable Control Arms
Most factory controls arms are non-adjustable, meaning they are on fixed mounts. Aftermarket companies like G Force Performance Products make adjustable versions.
Most commonly, adjustable control arms are used to position the rear-end housing in the chassis wherever you may need it. And, if required, changing the pinion angle to correct any driveshaft geometry is more easily done.
Adjustable control arms are used in numerous applications, from drag racing to extreme off-road 4-wheel drives. In our case, we created a set for the Jeep and off-road crowd.
New G Force Jeep Wrangler TJ Control Arms
What is a Johnny Joint?
Johnny Joints are also known as spherical rod ends, and they are crucial in off-road applications. When you look at the articulation, Jeeps are designed to go offroad.
When one wheel gets raised during off-road driving, it shifts the whole axle, but not only vertically. The control arms also want to twist or articulate to accommodate for the change in angle.
Rubber or Poly bushings will not allow this kind of travel, and they will bind up and restrict the amount of articulation. The G Force control arms eliminate this problem by using the Johnny Joints on both ends of the upper and lower control arms.
Control Arm Installation Tips
G Force Performance Products includes thorough, step-by-step instructions on installing specific upper and lower control arms at the time of purchase.
Installation of the G Force upper and lower controls arms is not difficult and requires only hand tools. Tools you will need to install the control arms are a floor jack, jack stands, ratchet, and a socket set.
Install Upper Control Arms First
We suggest removing and replacing the upper control arms first. The first step is to jack up the rear of the vehicle and install jack stands under the frame. By doing so, the axle is held in place by the lowers, making it easier to control the axle housing when installing the new parts.
Also, when pulling the upper control arms out, make sure to stabilize the rear end at the yoke with a jack stand to keep it from rotating. This precaution allows the rear-end to stay in position while installing the new uppers. Measure the distance between the mounting holes and mimic that distance on the control arms by holding each rod end and turning the center hex adjuster until the hole-to-hole spacing on the control arms matches your measurement. Then install the new arms.
Lower Control Arm Installation
After installing the uppers, you can remove the jack stand from the yoke and install the lowers. At this point, put a jack stand under each side of the axle housing, so it stays in place when removing the lowers. Once this is done, you can now swap out the factory lower with the new G Force Performance lower control arms, after matching the control arm length to your hole spacing like you did for the uppers.
Keep in mind that the installation is complete, and all the bolts are tight and torqued down. You will want to have the vehicle aligned
Control Arm Adjustment
The hex-shaped body is a significant feature of the G Force Performance Products control arms. The shape makes adjustments easier when changing pinion angles or centering the chassis' axle housing.
In conclusion, the G Force Performance upper and lower control arms for your Jeep are a terrific addition to your vehicle by giving you better articulation and alignment, stability, and strength.