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Greetings all.
I am the new custodian of an R63.
Trying to sort out some finicky bits on the car.
Firstly, I will be attacking the liftgate.
The hydraulic pump is bone dry.
I can't seen to find any mention on the min/max oil level when topping off.
There is a plus sign on the side of the reservoir that might indicate the fill level from horizontal and vertical positions but I don't want to guess.
You can drain it and then refill using the Febi hydraulic fluid
see these vidoes and they have one of Mercedes type in there https://www.youtube.com/@TopHydraulics
The pump uses basically the same fluid as the abc pump. When you fill it up, Fill it all the way to the plus sign when the cup is at the bottom. once the cylinder fills, you may add more fluid. It will foam until the air is out. The fluid is gone because the cylinder likely leaked. You can usually only buy the full part and the hoses are not for sale or rebuild. The hoses are crimped in place and can swivel so its inevitably going to leak in time. You can pay for a full rebuild, or what I did was use some metal weld around the leak (on a w220). I can send a pic if you need once you find the leak. Its the only diy repair I was able to find with exhaustive searching. I would not buy a used part personally.
I refilled mine. It was easy to do. Remove the spare tire and the cargo well cover to access the pump on the driver's side of the cargo well. I filled the empty reservoir a little more than half way and cycled to push the new fluid through the system.
The pump uses basically the same fluid as the abc pump. When you fill it up, Fill it all the way to the plus sign when the cup is at the bottom. once the cylinder fills, you may add more fluid. It will foam until the air is out. The fluid is gone because the cylinder likely leaked. You can usually only buy the full part and the hoses are not for sale or rebuild. The hoses are crimped in place and can swivel so its inevitably going to leak in time. You can pay for a full rebuild, or what I did was use some metal weld around the leak (on a w220). I can send a pic if you need once you find the leak. Its the only diy repair I was able to find with exhaustive searching. I would not buy a used part personally.
This is helpful.
Thank you mucho.
I'm sure I will have to replace the unit... unfortunately.
Last edited by Dr Kananga; Sep 3, 2024 at 02:55 PM.
This is helpful.
Thank you mucho.
I'm sure I will have to replace the unit... unfortunately.
any luck? When I did the s55 it took a couple tries, then finding the leak and sealing it. It wasn’t dry, but didn’t open consistently. It been perfect ever since.
Here are the steps:
Remove spare tire
Pull back grey cover on the side. It has tabs across the top and clip in at the base of the spare tire well.
Unclip and open the plastic box that holds the pump. You'll need to cut a zip tie for the cable and have a new zip tie to secure when finished
Pull out the pump and then you can fill up the fluid reservoir.
Hope that this helps!
Last edited by CarolinaR320; Sep 9, 2024 at 12:15 PM.
Reason: spelling
Here are the steps:
Remove spare tire
Pull back grey cover on the side. It has tabs across the top and clip in at the base of the spare tire well.
Unclip and open the plastic box that holds the pump. You'll need to cut a zip tie for the cable and have a new zip tie to secure when finished
Pull out the pump and then you can fill up the fluid reservoir.
Hope that this helps!
I pulled the spare out and looked all round the area, took out all the grey covers and especially paid attn to the left side where you show the pump - but - either the pump is elsewhere or PO has removed it? There was no trace of a pump or anything else under the grey cover on the left. Very odd!
So you don't have the black box in photo #3? On the GL the pump is located on the right side. Maybe MB moved it at some point? What year is your R class?
Hi, thanks for replying! My car is a 2006 R-class. No black box etc ...we thought if the pump had been removed there would still be some traces of it being there, like the hoses and electrical connectors perhaps? on the rightbside we have the fusebox btw.
My reservoir was completely empty so I just filled and cycled it. Refilling hasn't completely fixed the issue but it is a lot better. I think that my drivers side hydraulic actuator at the roof is the issue. I just give the rear lift gate a slight hand assist mid way down to close. When its colder, I need to help it open as well.
Would you purge the entire fluid before putting fresh new fluid. Mine is completely black. Thank you.
yes, when I did this with an older S class, I started with an empty reservoir and filled an empty multiple times till the fluid was nice and green, or red depending which fluid do you use. Of course, the greater question with any of these leaking pumps is have you fixed the leak? You can also think about using the product AT205 to help out with conditioning of the seals.
Greetings all:
Here is an update on the pump fluid. My rear hatch was acting up so I checked the pump reservoir. It was nearly empty. It was damp around the base of the reservoir. Turns out the reservoir cap wasn't entirely seated on the pump housing. I clicked it in place. I then filled the reservoir and cycled the pump several times. I needed to add a second round of fluid. I filled about 2/3 full. Oddly enough I just bought a pump, hoses and actuator from an R500 and it was 3/4 full. Next time I'll add more fluid...
Attached is a picture of the fluid that FCP Euro recommended for those who were asking about fluid type.
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