New R500 owner here with a huge mystery that no mechanic has been able to diagnose 100 percent yet. As noted in title, when accelerating weather form a stand still or passing someone one freeway, you get a havey pronounced shuddr that feels like its coming frm the back of the car. If i step on the gas heavily you dont feel anything. Its only when you modeatly accelerate. Happens every time cold or warm engine or outside temperaure doesnt make any difference. Also it makes no difference if its in C or S mode.

Problem number 2 is whne turning wheels all the way right or left and at low speeds or from sanding still the car will roll a couple of feet by itself without hitting the gas ( as normal ) but then will come to a complete stop as if i just hit the brakes to stop it and will not move unless i hit the gas really hard to move it and you can feel it fighting you back as if the brakes are applied.

Any ideas?? I read just about everything online regarding the aove two issues but there is nothing that duplicaes exactly what im experiencing.

I got several mechaics (mercedes and others) give me diagnosis from steering rack to differential to esp to transmission to angle sensors to speed sensors. Im ging insane trying to figure it out. I don't want to take it to mercedes dealer as i do not trust them.

The car is a R500 wth regular struts and 117k miles. The steering does moan when turning btw. Tranny shifts very smooth all the time. The Only true diagnostic i got is one high end shop hooked up their computer to it and told me its 100 percent the steering rack causing all this mayhem as thats the code they got from scanning the computer and it affects brakes as well. Is that possible?

Any input will be grealy appreciated.

 

There's an o-ring from power steering pump reservoir to power steering pump that is a very common leak. I had to change mine a couple months ago. When the power steering fluid leaks, not only does the level drop, but it also lets air into the system. Power steering with low fluid or air in the system will cause the power steering pump to groan as it's trying to pump air instead of fluid.


If left long enough, pump and steering rack can break.


1. Has it been confirmed PS fluid level is topped up
2. Has it been confirmed there are no leaks in the power steering system?


Note that when I had my leak I didn't get any codes!!!! Just terrible dying-cow-like moaning from the engine bay.

 

Thank you darkflash for your response. I will look into that. However, my problems as i described them are more involved. Any ideas.....anyone?? Im beginning to believe that im the only one with this problem so far. Please HELPPPPPP