Control Arm Bushing

What control arm bushings do

Control arms, sometimes called links, hold the axle in position front to back and side to side while letting it move up and down. The bushings at each end of the arm absorb vibration and permit the arm to pivot. When they wear, you may feel clunks, brake dive, drifting under acceleration or vague steering, and alignment can wander.

Materials

• Rubber gives the quietest ride and most isolation, but it softens and cracks over time.
• Polyurethane is firmer, holds shape and usually resists oil, though it can add noise and harshness if not lubricated correctly.
• Metal or spherical joints give precise control and high articulation, and they are common on heavy trail builds, but they transmit more noise.

Durometer ratings describe firmness. A stiffer bushing improves control but gives up some compliance and may bind with extreme articulation.

Choosing a kit

Kits are built for particular arms, so check the bushing's outer diameter, inner sleeve size, length and quantity. Some kits cover upper and lower arms, and others include only one. Replacement sleeve kits are also available for arms that need new inner sleeves. Aftermarket arms from lift manufacturers may use different bushing sizes than the original, so verify before choosing.

Installation tips

Bushings are usually pressed in and out, which calls for a press or a proper bushing tool. Heat can damage the surrounding metal and should be avoided unless you know the procedure. Support the axle properly and note the position of the arms. The most important step is to tighten the control arm bolts with the vehicle at normal ride height, so the bushings are not twisted. Torque to the manufacturer's specification. Because these parts affect axle location and steering feel, have a shop do the work if you are unsure, and get an alignment afterward. Look over the polyurethane or rubber for any pinching at the bolt sleeve once the bolts are torqued, and check the movement of the arm by hand before lowering the vehicle.

Fitment

Control arm designs differ by year, axle and whether the suspension has been lifted. Confirm fitment for your exact year, make and model, and check the manufacturer's specifications.

Inspection and related parts

When replacing control arm bushings, look at the arms themselves for bends, cracks near the welds and ovalized bolt holes. Replace the bolts if they are stretched or corroded. On a lifted vehicle, arms and bushings carry greater loads, so check them more often. Adjustable arms let you correct pinion angle or caster after a lift, and bushing choice then affects how much movement the joint allows. Bushing wear is often uneven, so replace all bushings on an axle at the same time. Afterward, verify the alignment and look for steering pull or vibration, since worn control arms can shift axle position.

Bushing replacement is a good time to refresh the bolts, nuts and washers. Use grade-rated hardware at the torque specified by the vehicle or arm maker, and apply thread locker only where it is recommended.