I have a 2000 ML320, with 107K miles. I believe that my power stearing pump has gone bad. The car drove fine, but a very load noise came from the pump, or so I thought. However, I replaced the pump, but the noise did not go away. Do you think this pump may also be bad, or is there something else that could be making the noise in the stearing rack. The car drives fine, no problems turning, but the noise gets loader when I turn.

Just out of curiousity;

Did anyone ever add transmission fluid to the pump or the previous one that was removed..?

Only trying to help, thanks.

What kind of noise.? Describe the noise? Screech, groan, squeek, bang, etc etc

No one has put transmission fluid in either pump, unless it happened at the dealership. I am the only one that services it. And to respond to the sound, it is more of a groan/whine sound, like the pump is working to hard.

If the previous pump got contaminated somehow then the new pump would get/be cross contaminated also as soon as it was installed in the system...

The pump is straining making a noise...

The previous pump did also...

Be interesting if a sample of the power steering fluid could be sent off to a laboratory for analysis...

Problem is automatic trans fluid is mighty close to power steering fluid in composition...

I believe the system was accidently or accidently/on purpose contaminated at some point in the cars history...

Prior to the previous pump being removed...

Just trying to help, thanks.

Post results.

HI Folk s
I have a 97 C 280(W202)
Does any one can help to post a picture or two in regards to changing power steering filter . Greately appreciated.
Thanks

A whining kind of dentist drill type sound is probably becuase of air in the system, my mercedes did the same and it simply needed topping up but on another car I had there was a leak somewhere in the pipes so no matter how fill the sytem was air was leaking in a making that sound! So have it checked for leaks before you replace another!