A few days ago, I replaced the short return hose between the power steering oil cooler and the reservoir. Doing so got air into the pump, as would be expected.

My first attempt at purging was to lift the front of the vehicle, run the engine at idle and turn the steering from one side to the other several times. This did not seem to purge any air from the system, but rather made the fluid in the reservior resemble a nice froth.

I drove it in this state for one day. Here's a suggestion: don't do it. The power steering was very bad, to the point that it would take a second or so to apply pressure when there was resistance at the wheels. Parking lots were no fun. Also, the air in the rack seemed to affect the damping, and there was a nice shimmy at about 55 mph which went away at higher speeds.

When it was in this state, the pump groaned loudly when any pressure was applied to the rack. You could hear it inside the car, and feel it vibrating the body.

My second attempt was that night. I let the car sit for a few hours and again raised the front, but this time turned the steering wheel from one side to the other a few times first. I heard the noise of air moving through fluid, so I checked the reservoir, and was happy to see that the level had dropped about a half an inch. So I topped off the reservoir and turned it some more, with the engine off. Then I started the engine and turned yet some more.

The power steering now feels like it should, so apparantly my purging technique worked well enough. But how are you supposed to do it?

You don't mention your car, but a lot of the late models 112 and 113 motors have a filter built into the PS reservoir. Sure sounds like yours is plugged. There is nothing to bleeding the system otherwise. Pour in fluid turn the steering lock to lock a couple times and air is gone, unless there is a problem and a restricted filter would be my first thought.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

W210, as in the title. It's a '96 E300, and the dealer claims that there is no filter, after looking up the VIN. I can't see one either.

My '99 210 doesn't have a filter either. '96 was about the time they disappeared as I understand it. Interesting that the parts houses still show my 210 as using the same filter as my 240D.

Len

From the looks of the reservoir in the parts program, it looks like diesel owners might be getting screwed. It looks similar to the gas reservoir only it isn't available separately. I can tell you from replacing a bunch of them that the groaning noise from a plugged filter is simple to fix on the v6 and v8s with the disposable reservoir. Based on the look I'll guess that the diesel also has a filter in its reservoir, it just isn't replacable.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician