Genuine BMW 31126786203 Control Arm; Rear Left – BMW

Control arms are the suspension links that connect your vehicle’s wheels to the chassis. They attach the wheel carriers and steering knuckles to the chassis or subframe using bushings and ball joints and act as hinges in the suspension for the wheels to move up and down following the contour of the road. Control arms also set vehicle wheel camber and caster alignment and can be adjustable.

Signs of Faulty Control Arms

Control arms fail when the bushings or ball joints that they are attached to wear out. Worn-out bushings cause the control arm to move excessively or place the wheel out of alignment. Worn-out ball joints also cause excessive movement and can even separate disconnecting the control arm from the steering knuckle. Rough terrain, hard accelerations, quick shifts from reverse to drive, and driving too fast over speed bumps can stress control arm bushings and ball joints, causing them to wear more quickly than usual.

Visual inspections of control arm bushings that reveal cracks indicate that the bushings have failed. To check for horizontal and vertical play in the wheel, lift the BMW, so the wheel is off the ground and hanging from the suspension. Excessive play can indicate that the ball joints are worn out. Vibrations in the steering wheel when accelerating or cornering, a steering wheel wandering back and forth while driving, vehicle clunks when turning, going over bumps or braking, vehicle drifting, wheel wobble, and uneven tire wear are all signs of control arm problems.

Replacing Your BMW Control Arms

Repairing control arms differ based on the type of control arms used on your BMW. Some control arms are impregnated with bushing and ball joints and will require replacement when the bushing or ball joint fails. Other control arms have a serviceable bushing and ball joints pressed into or bolted onto the control arm and are replaceable on their own. These only require the replacement of the control arm if the control arm is bent, cracked, or excessively rusted. When replacing or servicing control arms, it is always recommended to have the alignment of your BMW checked and adjusted to prevent additional uneven tire wear.

BMW Control Arms.