tacomeat

Hi all,
Purchased a 2005 C55 a few months back. It had a pulsation in the steering wheel unlike anything I had ever felt in any other car. Here are the steps taken since:

1. Full power steering fluid flush w/ lubricant (didn't fix issue)
2. Replaced pump reservoir (didn't fix issue)
3. Replaced pump (new) and rack (Bosch reman unit). (Issue was much improved but the pulsation still happens. Most noticeable when holding the wheel steady at 11 or 1 o'clock through a gentle curve).

I read at one point about an inline filter (I think?) in one one of the power steering lines that could fail potentially causing this issue, but I can't seem to find that thread.

Pretty pissed off at this point. Tried the cheap solutions, then the less cheap solution, then the really expensive replace everything solution and even that didn't work. Also love that the brand new valve cover gaskets we put in still leak. Trying hard to like this platform but so far it's a big ol' turd.

Any and all help appreciated, thanks.

Design4111

Tacomeat

I also do not have an idea why this is happening, but I have a question.

Do you have option 213 (speed sensitive steering)?
Check your data card if you are not sure.

tacomeat

Great question thanks.

It does NOT have the speed sensitive steering.

Design4111

Ok,

Again, I am just shooting in the dark, but what fluid did you use?

Did you use A001 989 24 03 13 ?

tacomeat

Pentosin CHF 11S

Erik C32

Did you try a different set of wheels? Is the vibration speed or RPM related?

tacomeat

It's something in the steering system, its a pulsation in the steering wheel, not a vibration. For example if I'm in a corner holding the steering wheel at 1 o'clock it will "pull" the wheel back towards center over and over. Symptoms have improved greatly since we installed the new pump and rack but are still present.

Design4111

Interesting

Could it be that they installed the power steering pump lines wrong way around. (i.e. you turn left but the pump pushes right)

On the rack, the lines are "side by side" according to me.

(PS, it is just a thought).

kaixdiego

if the symptoms are improving, could it be that the system had a ton of air enter and needs to be bled further?

On my ML55, it took me about three times bleeding it to get all the air out over a span of a week or so, they have the same ps pump. You are supposed to lift the car in the air and turn the wheel left and right full lock about 30-40 times (It is in the service manual to do this with the engine off, but I did it both engine off and on and didn't notice too much difference)

You can also do it on the ground, using two plates of cardboard sandwiched together with grease in between underneath each of your front tires. This is what I did with my C55 and it worked fine after flushing the fluid.

ricecooker713

There's a possibility that you have a partially collapsed power steering line. The inner sleeve would collapse which would restrict flow. I would highly suggest looking into this.

tacomeat

This is our working theory at this point. Degrading lines clogging up the seals on the rack causing them to fail. Issue continues to get worse the longer I drive it. Of course replacement lines can't be sourced so we're going to have to get some built.

Design4111

I am not sure if this will fit, but some lines are available.

https://www.ebay.com/itm/For-Mercede...YAAOSwdjdaDsHc

Design4111

You need 3 hoses in total

tacomeat

Yeah, we tried the one available hose that was supposed to fit and it didn't. Just going to get new ones made at this point.