2021 Mercedes-Benz S580 Steering Knuckle Replacement Cost

Whether or not a vehicle can be driven with issues related to the steering knuckle is dependent upon the specific component that is worn or failing (see individual components for more information: wheel hub, wheel bearing, control arm, tie rod end). The steering knuckle is not often a problem unless it has been damaged. If the threads to which the brake caliper is attached are damaged and the caliper cannot be secured (during brake service), the vehicle should not be driven until the steering knuckle has been replaced.

The steering knuckle should last the lifetime of the vehicle unless it becomes damaged.

Each component related to the steering knuckle wheel hub, bearing, ball joint, control arm, tie rod has its own set of symptoms and is diagnosed individually. The steering knuckle itself, when damaged, might show up as uneven wear on the inside or outside edges of the tires. Damage might also present itself during a suspension alignment. More likely are the related symptoms associated with the steering knuckle: “clunking sound” when going over bumps or in turns, “growling” noise from the suspension when driving, excessive play in the front wheels. Each of these symptoms can be diagnosed during a suspension inspection.

To replace a steering knuckle, a technician will need to lift and support the vehicle and remove the front wheel and tire. The brake caliper and brake hose will need to be detached from the knuckle and suspended out of the way and the brake rotor will be removed. Any electrical wires connected to the knuckle will need to be disconnected. The technician will detach the tie rod end, as well as the upper and lower control arms, and separate them from the steering knuckle. If the vehicle is front-wheel or four-wheel-drive, the axle shaft (“CV shaft” or “half-shaft”) will also have to be disconnected. The steering knuckle is then dislodged from the control arms and slid off the axle shaft. The wheel hub, bearing, and brake dust shield are removed, as is the wheel speed sensor. The new knuckle is then assembled and installed in the vehicle.

Wheel alignment should be checked and adjusted as necessary after a Steering Knuckle is replaced.

If a steering knuckle is replaced, the associated wheel bearing should be checked and replaced or serviced as necessary.

RepairPal recommends checking, and replacing if necessary, the wheel hub and bearing at the same time the steering knuckle is replaced. It is also good practice to inspect the tie rod end, ball joints, and control arm bushings. A four wheel alignment is recommended after the steering knuckle has been replaced.