Hello everyone. My steering pump has started groaning and getting worse.

First, is the pump the same as those on E55? If so, that gives me a bit more data because there are more results in the search which apply to that engine than the M156.

I did make sure it was full tonight and hot it was reading at the bottom of the cold range so filled it up. I am not however holding out hope that will resolve it.

From my research there are 3 possibilities. The first I am not sure applies, but I have read some high pressure hoses have a check valve that can get clogged. I do not see anything about that on E55/63 so I am assuming it has never been an issue or we do not have one. Another item it could be is a supposed filter integrated into the reservoir. I have no data that says my pump has this but it likely does. And third, the pump is simply going out and I should simply replace the whole thing.

I am hoping some of my E63 brethren have some experience on what they replaced when the PS pump got noisy. Still steers fine, but the groan is enough to be felt through the steering wheel.

Thanks,
Jon
P.S. Pump Reservoir PN in car is 000-466-90-02 which seems to have been replaced by 000-466-95-02

 

For the cost, I replaced the pump & reservoir at once. No more groan
Only challenging part of the job is accessing some of the bolts
Also have a long magnetic stick ready for when you drop a bolt or fumble the bolts inside the power steering pulley. Also I would recommend you get a pump with pulley already pressed on for ease of install.

 

I'm not sure if I have the same issue or not. When my car is warmed up and I turn left or right, the car make a strange low pitched squeaking / squealing noise.

What could this be?

 

My E63 started to sound like you describe. So I began preparing for the dreaded pump replacement. Lo and behold, it just needed some fluid despite the reservoir probe showed adequate level. I also know people who 'fixed' this by replacing fluid. Do not underestimate steering fluid. Hope this helps.

 

Thank. Filling with new fluid had it leak out.

Now is worse. PN for reservoir confusing. PN on current shown with replacement number but it is not shown as a fitment for my car. Ordering parts Monday

 

More info after crawling under the car. Somehow what I had thought the steering fluid would be the green of the CHF 11S I had changed in the reservoir. But no, engine oil color. And same in reservoir. Changed it out and put some absorbent pads on the splash shield to get me bye for a week.

 

First - big shout out to https://www.benzpartshq.com/ who helped me figure this out. They also have the cheapest price for rebuilt steering pumps.

Hotsauce55 - well you are not the first and not the last E55 owner to give advice to a E63 driver that did not apply to E63. Turns out the reservoir and pump are not connected by an O-ring. they are connected by a hose. No worries, the documentation from the parts suppliers matched what you said. My dealer gave me info but 2x the price on the reservoir.

There is an integrated filter. PN is 000-466-95-00 even though the picture looks nothing like that reservoir from the parts suppliers. There is no O-ring. No idea where it is leaking but will disassemble and let you all know.

 

Where did I give you advice on the E63? I simply said for the cost, I replaced my pump & reservoir. My advice was to replace the pump & reservoir based on my experience given the price.

If the E63 had no PS pump or reservoir then I could understand your comment.

 

Hotsauce. My apologies, I read it as having the reservoir pressed on.

I owe you a beer... next time I am in Ontario or you in SanFran bay area