This has been covered in various posts and various forums - but thought since did mine a week or so ago would post it up - Was going to take more pictures but it really is ridiculously simple.
Was shocked how bad my fluid was at 92,000kms (57,000miles) - see picture of first 2Ls or so - Black and burnt smelling - way past due for a change!......Will be switching mine out every 30-40,000kms from now on
Credit to those who have posted in various places before. Dont know if this method is the best but seemed logical - YMMV & DYOR
ABC filter part # 0031846101 (new style 3 micron)
13mm to 13mm hose connector (50c hardware store)
2-3m 13mm hose - clear is easiest ($7 hardware store)
Pentosin CHF-11S. I used about 8L for mine all up - but bought 12L just in case
1 small clean funnel (optional)
1 clean oil pump (optional)
1 extra person to start car and cycle suspension
*If you have SDS run a Rodeo. Otherwise cycle up and down 20-30 times - Fluid should be hot -(Note I did my flush after a 45 minute run in sport mode, cycling ABC up and down regularly during the drive then an additional 30 times on stopping prior to commencing below)
*Locate ABC reservior cap on LH front side of engine (Passenger side for RHD countries - Drivers side LHD) - it will have a 13mm return hose clamped to it. The ABC dipstick is next to it.
*Open ABC reservior cap - (Has ABC filter attached) remove filter - need to press on the spring - it is attached by a little hook in the seal - place aside on clean MF cloth.
*Undo clamp and take out return hose from ABC reservior cap
*Connect ABC return hose to 13mm connector (i reclamped) attach other side of 13mm connector to clear plastic hose (i clamped this as well) - see picture
*Run clear hose to bucket
*Prep your Pentosin cans ie open and pull up ready to pour.
*This step is optional but i did - use oil pump to remove ABC fluid in reservior and refill with new pentosin. (You could just start the below process without the syphoning out of the reservior)
*BE CAREFUL HERE - Dont let reservior run low/dry you will kill your pump.....Have an auto cut off word for your +1 so if needed they will turn engine off asap.
*Get your plus 1 in the car.
*Get your Pentosin in hand ready to fill through the ABC reservior cap space (I used a CLEAN funnel - again optional)
*Start engine, ABC fluid will pour out clear hose into the bucket. The fluid will drop at a steady pace so be ready with your pentosin and keep filling - however you should be able to keep up with it. (I was extra careful and stopped the engine a couple of times as i was swapping Pentosin cans)
*As you are filling get your assistant to raise and lower the suspension using the centre console button.
*Keep doing the up and down while filling while keeping an eye on the bucket. You will see the fluid slowly dropping the dark/black colour and get closer to the fresh fluid colour. Once you are happy with the cleanliness of the fluid (mine was 5L or so) turn off car.
*Get the spring and seal from earlier and put on new ABC micro filter (again press spring and attach via the hook - a bit fiddly here)
*Unclamp the return hose and remove the 13mm connector.
*Reattach return hose to reservior cap and reclamp
*If not already done top up ABC reservior - not too high as the filter etc has to go back in here - and you will use dipstick to correct the fluid level.
*Put filter in and close ABC reservior cap
You now need to get your fluid to the correct level - the dipstick has 2 readings Engine On ("Auf") - the lower indentation and Engine Off ("Aus") - the higher indentation.
I used the off "Aus" readings - up to you again which you want to do.
for Engine off - car has to be left for 5 minutes on level ground at low suspension setting and should be between the top indentation on dipstick. (I checked after standing cycles & bleed as per below, then a quick run with sport mode and more cycles - parked again and rechecked - then rechecked a week later)
for Engine on - level should be constant at the lower indentation.
*Run a final bleed on the system - if you have SDS run a Rodeo. Otherwise cycle up and down 15-20 times
*Final level check of oil level
Official process calls for 2 filters (i think the above method is fine but up to you)
I referred to the below as well:
Youtube video of fluid check & filter change:
Mercedes official docs through the years: see attached