A few months ago, the StangNet Staff gave you an illustrated writeup on how to install the J&M Adjustable Upper Control Arm on a 2005 Ford Mustang.  Now, we are back to give you some additional information regarding the reasoning behind the finely crafted piece, some specs, and most importantly, where to get the part! This rear suspension piece is crucial and eliminates the unwanted control arm flex, resulting in more sure-footed handling when you need it most.  Keep reading to get the full description straight from the trusted source, J&M Products.

Product Description

Just like the lower control arm bushings in the Mustang the upper control arm can have a significant impact on the vehicle’s ride, comfort, handling, acceleration, noise and vibration. When the car leans (i.e., rolls) in a turn, one side of the chassis moves upward relative to the rear axle, the other side moves downward, and the upper control arm must twist (rotate) to allow for the axle to articulate through its suspension travel. This rotation causes the control arm bushing to bind. If this bind becomes excessive, it will raise the rear wheel rate and produce sudden, uncontrolled, undesirable changes in handling (e.g., snap oversteer).

Ford minimizes this suspension bind by using compliant rubber bushings in the upper control arm. This very “soft” bushings help accommodate the necessary motion of the control arms during body roll. However, the rubber bushing does not provide much in the way of forward and aft support, which can cause wheel hop during hard acceleration and braking. It has become common practice to replace the stock rubber control arm bushings with solid or two piece polyurethane bushings to resolve the shortcomings of the soft rubber bushings. Hard polyurethane bushings eliminate wheel hop, reduce axle deflection, and improves straight line grip. However, the downside of common aftermarket bushings such as delrin, steel, stiffer rubber, solid or two piece polyurethane bushings is they prevent the necessary movement of the control arm during body roll, which in turn produces significant binding in the suspension when the vehicle is cornering. The polyurethane bushings also place unnecessary high stresses on the upper torque box mount, which is the attachment point for the control arm to the chassis. Standard aftermarket control arms do not allow for rotation of the control arm during cornering because of the stiffness of the bushings.

The Solution

J&M Products designed and built a tubular upper control arm which will eliminate the unwanted uncontrolled control arm flex. Round tubing is harder to work with but has many other advantages over square or rectangular tubing. It is stronger in bending, torsion, and also lighter than square or rectangular tubing.

We then solved the shortcomings of the factory rubber and other aftermarket polyurethane and stiffer rubber bushings. This was accomplished with our new Extreme Joint. By spending countless hours looking and dissecting the geometry and the need of the rear suspension we come out with bind-free bushings set up. Our Extreme Joint bushing design incorporates a steel inner ball which is surrounded by polyurethane outer cups. This combination allows the bushing to articulate like a spherical bearing during cornering but the steel inner ball does not allow the bushing to deflect during acceleration giving you great traction during acceleration like solid bushings but remains completely bind free like a spherical bearing during cornering for great predictable traction in the corners.

• Street/Race Version uses our Bind Free Extreme Joint Bushing Design
• Reduces wheel hop & improves traction by eliminating control arm flex!
• Rugged 1″-14 threaded bungs and adjuster for added strength over convential 3/4″ threads
• Custom made pinion snubbers for a proper fit and finish
• Durable black or red powder coated finish
• One piece folded saddle axle housing mount for a stronger design
• On Car Double Adjustable for easy adjustment

Part # WD 23990B (Street/Race Extreme Joint) fits the 2005 through present S197 Mustang and is black in color.

Part # WD 23990R (Street/Race Extreme Joint) fits the 2005 through present S197 Ford Mustang and is red in color.

Click here to purchase the J&M Upper Control Arm.