2004 Mercedes-Benz ML500 Tie Rod Replacement Cost

There are at least two inner tie rods per vehicle. When the steering wheel is turned, the inner tie rods will pivot to allow the wheel to move, and either push or pull the wheel to steer the vehicle. They are connected to the wheel via the outer tie rod end and experience much less wear and tear than the outer tie rod end.

Failing tie rods can create the sensation of a slight shift in the steering wheel, and an associated bump, click or pop noise. Turning the steering wheel while sitting still will make these same clicks, pops and bumps, and the vibration will be felt through the steering wheel. In extreme situations one wheel will noticeably steer independently of the other, without input from the steering wheel. 

When tie rods fail, and the mentioned symptoms are noticed, you'll usually have at least a few days to drive the vehicle to a repair shop before safety concerns should be raised. But as the ball-in-socket joints wear out, they'll slowly grind away metal that will eventually allow them to separate — a very dangerous situation.

Inner tie rods don't typically need to be serviced. They're usually only replaced after a traffic accident or other physical damage, or when the outer tie rod end fails and damages it. When the outer tie rod end allows the wheel play, it acts as a hammer and chisel, slowing destroying the inner tie rod end ball-in-socket.

The technician will check the undercarriage for signs of steering and suspension component failure. If the inner tie rod has any movement in the ball-in-socket joint, or is otherwise physically damaged, it will be considered ruined.

On cars or trucks with a steering gearbox, the vehicle will be lifted, and the wheel in question will be removed before turning the steering wheel the complete other direction. Once inner or outer tie rod is exposed, the castle nut will be removed. The tie rod can then be taken off. A wheel alignment will be necessary once the new one is in place. Cars with steering racks are slightly different. The vehicle is raised and stripped of the wheel, outer tie rod, steering rack and inner tie rod dust boot. A special tool is needed to remove the inner tie rod. Other parts may also need to be removed to gain access.

After removing the steering rack dust boots, the presence of power steering fluid could indicate a failed seal, and replacement of the steering rack will be recommended.

Only someone with a lot of suspension and steering system knowledge should attempt this repair. It's usually best left to professional repair shops.