m5zealot

So embarrassed to admit after doing a lot of ABC preventive maintenance on my SL55 (2006) including a full flush and pressure regulators, I didn't know I had a separate power steering reservoir! Now before you all start laughing, I know the ABC and power steering pump are one and the same (tandem). So naturally I assumed they share the same Pentosin from the same big reservoir. Yesterday I finally notice the "smaller" reservoir right behind it and the fluid was nasty.



I searched in vain for flushing procedures for R230 and didn't find any. Youtube had a whole bunch on S and E class diesels. I finally have a plan but just need to know which of these two lines is the return hose from the pump? Is it the smaller or larger? The return line is where I will hook up my trusty clear rubber hose for the flush. I'm assuming the other two smaller "pipes are vacuum lines? I attached pics from Google.

Thanks in advance for any other tips.

kbob999

While this may not be the official MB approved method, I will describe what I have done on my cars.

Suck out the reservoir with a turkey baster, then refill with fresh fluid.
Start the car and turn the front wheels lock to lock. Shut off the car.
Repeat the suck out and fill until the fluid is fresh.

HLG600

That engine bay is gorgeous.

I don't believe a return to the pump is accurate. The return line typically goes to the reservoir and the filtered fluid is then routed into the pump.

In any case, you don't need to "flush" the system if all you are doing is a fluid change.

1. Turn the ignition to Position 2.
2. Extract fluid from the reservoir.
3. Refill with new fluid.
4. Turn the wheel lock-to-lock a few times.
5. Repeat steps 2-4 until the fluid extracted is clean.

On a separate note, curious about your setup that is connected to the ABC reservoir cap. Can you share some details on what was done there?

m5zealot

Thanks for the suggestions! The procedure I was going to do is pretty much the same except, I was going to detach the return line from the reservoir and hook up my clear hose set up that I already had from my ABC flush months ago. This way all the dirty fluid goes into a bucket instead of mixing with the clean Pentosin I'll be pouring in. I know "Dilute to un-pollute" rule stands but, this will take as more old fluid out and not risking air getting into the system. Of course as you suggested, I will have my assistant turn the wheel back and forth (wheels off the ground) to expel the old fluid into a bucket. I just needed to confirm which hose was the return line. From looking at a parts diagram online, the bigger hose is the return line.

m5zealot

Thanks for your suggestion! The set up I have is the magnetic clear filter housing I got from Zaedow Automotive in Germany. Many in here have it. I simply used "faux" anodized braided line connectors commonly used by the hot rodders.

HLG600

My pleasure and thank you for the info w/ detailed photos! How often do you have to replace it?

m5zealot

I just installed it after a flush of the ABC system . I believe it’s reusable. It didn’t come with a manual bit the unit looks like it can be disassembled for cleaning. Maybe others can chime in?

kittyandgary

To completely purge the PS system, I too removed the top, used the suction tool (turkey baster etc.) to remove the reservoir fluid,. Then, I disconnected the line from the steering rack on the passenger side. By turning the wheel back and forth (wheels off the ground, engine not running), I was able to completely remove the fluid from the rack. Put about a pint of fluid in the reservoir and repeated the purging of the rack by turning the steering wheel to L and R stop a few times. Re-attached the line to the rack, filled the reservoir, with engine idling, turned steering wheel L & R 4 or 5 times. Then refilled reservoir to proper level. Maybe 15 drops of old fluid remained in the system, but 99% was fresh fluid.

Gary

m5zealot

[QUOTE=kittyandgary;8162500]To completely purge the PS system, I too removed the top, used the suction tool (turkey baster etc.) to remove the reservoir fluid,. Then, I disconnected the line from the steering rack on the passenger side. By turning the wheel back and forth (wheels off the ground, engine not running), I was able to completely remove the fluid from the rack. Put about a pint of fluid in the reservoir and repeated the purging of the rack by turning the steering wheel to L and R stop a few times. Re-attached the line to the rack, filled the reservoir, with engine idling, turned steering wheel L & R 4 or 5 times. Then refilled reservoir to proper level. Maybe 15 drops of old fluid remained in the system, but 99% was fresh fluid.

Gary[/QUO

This is the method I ended up doing because the return hose to the reservoir would have been a challenge to remove. Eyeing it - removal of the ABC reservoir would have been necessary to get the hose off without damaging it. This method does require more fresh fluid since you are basically diluting the old fluid with new. My fluid was pretty nasty so even 80% was good enough for me.

Frederick NL

WIS warns for air entering the PAS system while flushing/filling.

m5zealot

Yes I think everyone who do this DYI knows of that warning. As long as the reservoir is never allowed to run dry - that is why an assistant is important - the system will only continue to suck fluid not air. No air in my system after doing this method - no noises or error codes.