Mercedes-Benz ML55 AMG Rack and Pinion Replacement Cost

The steering rack is located between the front wheels, and attaches them to the steering wheel. The inner and outer tie rod ends link the ends of the steering rack to the steering knuckles, which is what the car's wheels attach to. When the steering wheel is turned, the steering rack forces all of these components out on one side, and pulls them in on the other side.

A failing steering rack may clunk when turning or when going over bumps.

Turning easily in one direction, but with difficulty in the other, is an indication of a problem with the steering rack.

Rack-and-pinion problems typically come with the following symptoms:

Power steering fluid leaks

A whining or clunking noise when turning the steering wheel

Difficulty steering at low speeds, or a loose sensation when turning the wheel

» LEARN MORE: How your steering system works

Small power steering leaks won't prevent the vehicle from driving, but when fluid cannot be added quickly enough to keep the pump full, a tow truck is recommended to avoid damaging the fuel pump and steering gear.

As any system that carries high pressure will, the system will eventually fail from normal wear and tear, but this should be well into the serviceable life of the vehicle. For most vehicles, the power steering system will last well over 100,000 miles before any failures occur. Keeping the power steering fluid fresh and the system free of contaminants is key to ensuring long power steering system life. That's why sticking to your regularly scheduled maintenance, detailed in your owner's manual, is so important.

Since most power steering issues generate the same symptoms, it can be difficult to diagnose one part without checking the condition of the whole system. A technician will check for leaks, examine the belt tension and listen for problems with the power steering pump. If these all check out. After that, if no other issues are found, the steering rack will be suspected of failure, if the symptoms dictate. 

Problems with the power steering control module (where applicable) can imitate problems with the steering rack. Be sure that the problem has been properly diagnosed before replacing an expensive steering rack.

Replacing the steering rack involves a fair amount of disassembly — fluid must be drained, hoses and electrical connectors must be removed, and the rack has to be unbolted from the car. Replacement is the opposite order of operations, followed by standard fill and bleed procedures for power steering systems.