1994 Mercedes-Benz E420 Steering Center Link Replacement Cost

For steering systems that use a steering gear or a power steering gear, the gear will be on one side of the vehicle, but turns both front wheels. To facilitate this action, a centerlink is used to transfer the push or pull from the steering gear to the other side of the front of the vehicle. It is just a solid piece of metal with a hole in each end so it can connect to the pitman arm and idler arm. It also has another set of holes on the ends for the tie rods. Some centerlinks have the ball joint installed directly in the ends, and are not serviceable.

To understand how the centerlink works, you must understand the pitman arm and idler arm. The pitman arm is connected directly to the steering gear on one end, and it connects to the centerlink on the other end. When the steering wheel is turned, the steering gear turns the pitman arm, which pushes or pulls the centerlink. On the other side of the vehicle, the centerlink is connected to the idler arm, which is bolted to the frame and centerlink, and turns with the centerlink whenever the steering gear pushes or pulls this assembly. With that knowledge, it should not be surprising to find that the centerlink also attaches to the tie rods, which push and pull the wheels when the steering gear turns. This is how a steering gear type front end operates, and goes to show how the centerlink received its name.

The centerlink will not typically wear out, as it is just a piece of metal with for holes, however, some types of centerlinks have ball joints installed on the ends instead of holes, and those ball joints can wear out, and necessitate replacement of the centrelink or end links. When one of the ball joints for the centrelink has failed, a clunking or popping noise will develop while turning, and the steering wheel will begin to feel loose and appear off-centered while driving. Also, physical damage to the centerlink calls for replacement, as a bent centrelink will distort the steering geometry of the vehicle, and typically the passenger wheel will point too far towards the centerline of the vehicle. This will be noticeable by feathering on the tire, and possibly extreme tire wear on the shoulders.

If the centerlink ends or centerlink assembly is not replaced immediately, tire wear will likely become more expensive than the repair and alignment. Furthermore, driving with a clunking or popping center link end ball joint will eventually lead to the separation of that ball joint, causing loss of steering control. To avoid these scenarios, the centerlink or end links should be replaced as necessary, without undue delay.

A typical centrelink will not go bad. Again, it is just a piece of metal with four holes. However, if the centerline uses end links with ball joints or the centerlink has ball joints installed on the ends, expect those to last as long as a tie rod end, which is anywhere from 75,000 to 150,000 miles. Keeping the ball joints properly lubed, avoiding potholes, and gentle driving will extend the life of the entire front suspension.

When diagnosing a clunking or popping noise from the front end, the centerlink, as well as all other front end components, will be checked for excess movement, and lack of firmness in the ball joints. If the centerlink is found to move too easily, or the technician can manipulate the centerlink to replicate the noise, it will be replaced.

The type of centerlink will determine the service procedure. If the centrelink has service end links, those will be replaced but loosening a clamp, using a ball joint separator to remove the ball joint from the idler arm and pitman arm, and finally unscrewing the end link from the centerlink. If the centerlink is one solid piece, the centerlink will be separated from the vehicle using a ball joint seperator on all four ball joints after removing the fasteners for those ball joints. Once removed, the new centrelink is installed, the ball joints are torqued to specification, and the vehicle is checked for proper alignment.

When inspecting the steering centerlink for faulty ball joints, it is important to check that the ball joint retaining nut is tightened to specification if movement is found.

Though the centerlink looks like a strong place to place a jack, lifting a vehicle from the steering centerlink will likely cause warpage in the centrelink, or separation of one or more ball joints. Beside these hazards, if the center link ball joints fail, the vehicle could collapse while lifting.

With a good set of ball joint separators, changing the centerlink is a very easy job. The average DIYer could inspect, diagnose, and repair a failed centrelink without difficulty as long as all safety precautions are exercised, and the proper tooling is used.