mallique

I have a 2008 ML550. Two years ago I found out that there is a small power steering fluid leak. Every year I have to top off the power steering fluid. Other than that I have not had any issues with the vehicle. But, recently the vehicle started loosing power in the steering wheel. It looses power every time I put the vehicle in Park (But the engine still running) or if the vehicle comes to a stop (at a stop sign or light), or if I try to steer while the vehicle moves very slowly (parallel parking, pulling in to a parking space and backing out of one, etc…). What I have also notices is that when I have the vehicle in Park and the engine running, if I put my foot on the gas pedal, the steering wheel gains full power and works perfectly fine.
Has anyone experienced this issue? What is the reason for this issue? What needs to be done to fix it?

Thank you,

Mallique.

Plutoe

I woulden't rush into things---but you power steering pump is going bad---wait another couple of years and it will stop all together---then fix !!

marc hanna

You need t replace the power steering pump. It's a hydraulic pump driven by the serpentine belt. It's not able to build enough hydraulic pressure at low RPM anymore in order to function properly. You'll find the same issue with any hydraulic pump.

Anyway to answer your question, yes, I had the same problem on my ML320. Unless you're getting rid of the vehicle soon, don't buy a cheap rebuilt one; it won't last very long.

mallique

I am assuming it is going to be a costly repair. Besides the Dealer, is there a place I can purchase the pump for less? How much did it cost you to replce the the pump in your vehicle?

Also do you think the pump went bad due to the fluid leak in the steering wheel rack? Will I be able to fix the fluid leak by replacing just the seal / valve, or do I need to replace the entire rack?

marc hanna

You can get the pump from Amazon. Cardone makes good rebuilt ones, but other than that avoid rebuilt ones because you won't know what you're getting. You should be able to get one for between $150 and $200.

Being low on fluid can cause it's early demise. As far the leak goes, it depends on where the leak is. There's a good chance the banjo bolts connecting the hydraulic lines are corroded. This means the rack is probably fine, but you will need to replace those hydraulic lines also.