Filling an empty R230 ABC system.

Page may contain affiliate links. Please see terms for details.


Active Member
Apr 30, 2019
London, UK
E350 S212 M272 3.5 // SL 500 R230 M113 5.0
Evening all,

To preface this - I am in the process of completing a full on overhaul of the ABC system on my R230 SL 500 .. all pipes out (except front to back) and cleaned/painted and hoses replaced. I have a build thread on another MB forum, and plan on posting it all up here, for anybody interested.

I'm probably about 90% there. Remaining tasks are to finalise plumbing and re-fit the struts.

One of the remaining uncertain tasks is that of priming the pump and filling the system, and I am interested to hear how others have gone about it.

For priming, I was going to undo the line from the pump into the pulsation dampener and then add fluid and air pressure to the reservoir until it reaches that open line. I would then be sure the pump has fluid.

In the following pic, I would undo the rear most line (from pump to dampener) to check for fluid.


Then to fill the system.. how quickly will the pump suck in fluid, and empty the reservoir when the system is completely empty? I can see the following strategies:

1) Just start the engine and fill the reservoir as it drains - Keep It Simple, Stuid! (I would initially fill each strut though).
2) Try and use some external air pressure to fill the system, something like an transmission fluid pump kit.. getting as close to 10 litres into the system before starting the engine.

I know air compresses so it shouldn't really damage anything if there is a load of it in the system when it gets charged... but just checking.

I am talking about the initial fill here, I know that once there is a bit of fluid in the system I'll have the bleed valves in each corner open and draining off. Once the obvious air pockets are gone, i'll run a few rodeo sessions to bleed off the rest.

What fluid are people comfortable using.. I see a huge selection of CHF11S compatible fluids on the market. In my system I use Comma MVCHF via Halfords trade for the best price.

P.S. Anybody used the X8R valve rebuild kit.. I have had an issue with some of the O rings being smaller than original and really unsure about firing up the system with them.

If you read this far, thank you... and as an easter egg, here is a quick before and after of the rear underside, freshly epoxied and painted after blasting. I am really happy with it.

20231211_213941 copy.jpg

20240320_231414 copy.jpg

20240406_151618 copy.jpg
When pressurising the system with workshop air into the ABC fluid tank keep an eye in the pressure via scan tool as shown here. 18 minutes 30 seconds in .

To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

Users who are viewing this thread

Top Bottom