Power Steering Fluid Change

How do I change the fluid and filter in the power steering pump for a w123? I can't find anything on this topic from the service manual CD

[engatwork]

I suck it out with the MightyVac. Once you take the fluid out of the reservoir you should be able to see the filter. I usually just refill it, drive it and do it again. Three or four times of this procedure should pretty much change it all.

Thanks, sounds easy enough. However, I don't have a MightyVac, can I use something such as a siphon tube?

[JHZR2]

simple, go to autozone and ask for a cheap hand siphon. I paid 99c for the little one they have there. You put the tube into the bottom of the reservoir(the filter actually has holes in it so if you fish around enough youll get the tube stuck in one of the holes and not have to worry about it), then squeeze the siphon and drain it into your used oil. I usually fill it up once, keeping the old filter in there(they are cheap, if you want to do a super good job, you could replace the filter each time... I suppose Im introducing junk into the new fluid by way of the old filter) using the cheapo power steering fluid, then siphon that out, taking out the old filter and making sure that all the fluid is out of the deep recesses of the reservoir, then clean out any stains on the reseroir walls, put in new filter, and fill it up with MB power steering fluid. all in all takes maybe 30 mins max, most of that time waiting to get thte fluid out. If you had a little hand operated pump, topsider, etc that pulls a little better vacuum then a siphon, it would be MUCH faster.

Oh yeah, to get the filter off, do the following; the filter is presed down tight via a spring, and a little triangular piece of metal that keeps the sprig down. pull up the piece of metal with your hand or small pliers(just play with it, it will come off easy), then pull the spring ff the shaft, and pull the filter out...

Hope this helps

JMH

[Stevo]

Go into the kitchen when your wife is away and nab the turkey baster or better yet get one of those bulb things that were made (I think) for adding water to batterys, works great. I use a length of brazing rod with a little hook in it for getting out the filter. A coat hanger would work. Good luck

[Billybob]

This is a copy of an earlier post I made on PS Fluid R&R. The conscious is that as much of the old fluid as possible is best removed given time and tool constraints and replacement with good quality "life blood" to avoid system degradation and resultant failure. As the heart of the system is a continuously running hydraulic pump and ensuring that clean fluid meeting required specs is cheap insurance for expensive parts. i use my 12V pump to drain engine oil and tranny fluid so it was a natural to make use of it in this similar draining job. Good Luck!

Power Steering Flush/
I just flushed and replaced filter on my SDL so I don't know how similar the Process would be but it worked well for me.
I used my home built 12v electric topside pump to remove the old fluid. Get the fluid warm first.

1. Disconnect the low pressure return line coming from the steering gear. I was able to disconnect mine by releasing a spring clip that hold the hose to a hard pipe fitting that empties into the PS pump sump. I disconnected it here because it was easy to plug the hard pipe quickly preventing fluid from flowing out and when you quickly elevate the return hose end you prevent fluid flowing out of that end.

2. Attached my suction pump inlet the return hose. A 3/8 OD polyethylene hose fit inside the return line perfectly.

3. Remove PS pump cover and start the suction pump. As fluid level in reservoir sinks stop pump when the filter is exposed and the fluid appears to be at the bottom level of the filter. You can look at the small space between the filter and the sump housing.

4. Remove the threaded stem holding the filter and the filter, replace with the new filter and reinstall the stem.

5. Top off the sump with new fluid. Start suction pump. the new fluid will be pulled through the pump, the pressure line, and the steering gear, out the return line by the suction pump. I pumped my old fluid into a clear 3 liter soda bottle. I kept an eye on the fluid level and added new fluid as the level decreased keep the level at 1/2 full. I had my daughter sit in the car and kept her turning the wheel from left to right and back as often and far as she could. When the fluid coming out of the return line was clean, stop the suction pump. System capacity is 1.2 Qt. I think I used about 2.5 Qt. during this flushing.

6. Replace the PS sump cover, remove pump from return line and quickly place the return line back on the hard pipe fitting that you have just quickly revved the plug from. Replace the spring clip securing the return hose to the hard pipe fitting.

7. Remove the PS sump cover and start her up. Have some new fluid handy and add enough to keep the fluid level at 1/2 full if needed. Have your helper turn the wheel from stop to stop a couple of times. Let the fluid get warm and then fill to the proper level. I filled to 1/2" below the top. replace the cover gasket, mine was hard and brittle. Put the cover on and your done.

8. I kept the cover on and sealed when disconnecting and connecting the return line in order to use the inherent vacuum to eliminate or reduce the flow of fluid out of the sump and return line. very little came out of either during the process. I placed my finger over the hard pipe end immediately and then quickly placed a rubber plug over the pipe end. I used a small rubber protective cap from some other part that I found and that fit snug you could make one easily by using a short piece of the proper size hose that has one end plugged. I used an outside plug because I figured it would be quicker and easier than inserting an inside plug into the pipe. After the change the new fluid was not pristine, a small amount of the old fluid was mixed into the new but was infinitely better than the old. I assume that getting all old fluid out could be accomplished with repeated procedures. Everything sounds and has been working great since. Some people blow off the filter stating that MB has eliminated them in newer cars but they filter only cost $2-3 so its cheap insurance for a PS pump or PS gear. My car may be different but the same procedure should work on most. Good Luck.

the rest of the discussion is here;
power steering fluid change 300E

[rickjordan]

I know that there is some debate about this but, the owner's manual for the W123 states to use ATF for the power steering. Even modern Mercedes take ATF or MB power steering fluid. Just some food for thought

[ajb]

Here is a DIY power steering fluid change from the FAQ page:

http://mbdieseldiy.tripod.com/ps.htm

Aivars