Uppers (get them cheaper from Summit/Jegs)
Ford Racing Rear Upper Control Arms, includes chassis side bushing only, 1979-04
These Ford rear upper control arms are direct replacements for the 1979-2004 Mustang (non-IRS) control arms. They will restore performance lost to old and deteriorating rubber bushings. These control arms have the stiffest rubber bushings available, and are much stiffer than what came originally on the Fox chassis Mustangs. Although Ford Racing Performance Parts claims their bushings to be "twice as stiff" as stock, our testing has shown that while they are much stiffer than Fox chassis bushings, they are identical to the 1994-04 bushings.
We performed extensive testing of rear upper control arm bushing materials during the development of our Panhard Bar. When retaining the original four-link suspension, the best compromise between resistance to suspension bind, best control of axle position, best ride quality, and least potential damage to the chassis, is to retain rubber bushings in the rear upper control arms. This is especially important when adding a Panhard Bar. The compliance of a rubber-bushed upper control arm is required when a Panhard bar is added to the Mustang four-link suspension.
When installed on a 1979-93 Mustang, these control arms with their stiffer bushings help limit axle wind-up and side-to-side motion, but will not damage your Mustang's upper torque boxes as a standard urethane-bushed upper control arm would. See our extended technical information about bushing material choices in our Rear Lower Control Arm section.
Lowers - (get them cheaper from a dealer)
What sets MM Rear Lower Control Arms apart from all the rest?
It?s the engineering expertise we put into our unique bushing designs. Instead of simply making control arms the same way as everyone else, we first analyzed the Mustang?s rear suspension geometry, and then designed control arm bushings to provide what is needed to improve traction and handling. The superior design of MM rear lower control arms increases traction, without the poor handling characteristics commonly caused by most other aftermarket control arms.
The rear control arms connect the rear axle housing to the chassis. All of the forces that accelerate the car, as well as the braking loads, pass through the rear control arms. In stock form, the deflection of the rubber bushings prevents the rear axle from maintaining its correct position under the chassis, leading to instability from rear steer. During acceleration, the rear tires push the axle forward, which in turn moves the car forward by pushing on the rear lower control arms. Replacing the rear lower control arms with MM control arms will improve traction and handling primarily because of the elimination of the overly compliant stock rubber bushings. With MM rear lower control arms, the properly designed bushing mounted in a stout tubular arm keeps the axle correctly positioned under the chassis. Traction and handling are both improved because the axle does not move around in an unpredictable manner.
Most aftermarket rear control arms use hard 2-piece urethane bushings, Delrin bushings, or steel bushings. Those types of bushings do not allow the angularity needed for the Mustang?s suspension to articulate freely. The resulting suspension bind causes the rear tires to break loose very easily. Suspension bind not only causes poor handling and poor traction, but it also causes damage to the torque-boxes. As the attachment points on the chassis for the rear control arms, the torque-boxes can suffer greatly from the abuse of poorly designed control arm bushings. After all, the torque boxes are only made of folded sheet metal