Thanks for your video. I was able to fix this issue in 10 mins with clear instructions. Appreciated.

on the earlier oil comments . power steering fluid or transmission oil are both hydraulic oils and would prob. work. the red fluid would be easy to see in resevoir.

Great Video! This is a big secret at Mercedes. Thank you for sharing the location.

Thank you!!! My ML63 pump was whining and grinding from cavitation. I found the pump reservoir dry with no single drop. So I added Mercedes hydraulic steering fluid and its smooth and quiet.

Good deal, mine has stopped going all the way up so I will check this tomorrow.

Want to add this video saved me from disabling the system and converting to manual. The tailgate would open fully with no problem but when closing it would bounce (kind of drop), stop, return to full open, and beep. I added fluid as the reservoir was nearly empty. Now, I may have a leak and time will tell, but in the meantime this is a fix. On my 2011 W164, there isn't a line, just a circle and when filled to the circle with the unit upright (vertical, reservoir on top), the system operates properly. As others have stated, Aircraft Spruce carries Aeroshell 41, a fluid that passes mercedes 342.0 fluid specs for this hydraulic system. If this does not fix the issue (long term) I intend to disable the auto tailgate and convert it to manual, as per a handy fcp euro blog.

Very informative video! Gonna try this! Thanks for sharing!

Damn I found this video on something totally unrelated to what I’m looking for but I’ve been wondering what the Hells been wrong with my hatch for a year now I want to head and added your video to my playlist on On my Benz

can you do a more indepth review on whats inside the rear corepanels in both side and besides under the fluid pump

Wheres the fluid going? Is there a common leak point?

Excellent vid. I was wondering where this pump was! One question (and hopefully you're still reviewing comments on this vid), was there a need to prime the pump or bleed it to get out any air bubbles? I saw that mentioned on a forum but didn't see you do this and wouldn't know how to do this w/o some instructions. Thanks!

1. Thanks for researching the replacement fluid - useful info. Aircraft spruce seems to carry aeroshell 41. I am sure there are other suitable hydraulic oils - the mercedes oil has a peculiar stink to it and is very low viscosity. 2. Looking at the way the pump works I don't think there really is a maximum level - it is basically a piston pump driven by an eccentric cam. Sure fill it to the level but I don't think going over would affect anything. The pump is fed through a shaft in the middle of the housing so that is the critical level 3. The common failure is the connectors corrode - clean with contact cleaner and put some white lithium grease on them. Grease everything and the motor pump should last for a long time. Shame on mercedes for such crap execution - they stuck it in a foam condom at the bottom of the trunk, what did they expect? 4. Regarding cleaning the pump of 'dried residue'. its a hydraulic pump! There will be no 'dried residue'. Sure take it apart if you are curious - be careful when you remove the bronze pump body, it is full of tiny hardened pins that will disappear forever when they fall on the floor. Disassemble over a suitably deep dish. There is a solenoid valve and some very small o-rings and that is about it. 4. In answer to Marco, the passenger rear contains the fusebox and SAM - the SAM is prone to death because water leaks through the rear lens and shorts the circuit board. typical modern mercedes - no conformal coating even though there is no justification - it is all low power. They could have put it in a sealed box but no and these things have been dying in this manner for 10+ years. In the u.s. the box is 400 delivered new, in Canada they give you a 'refurbed' one for 950$ and the core is 350$. And they will insist on programming it whether it needs it or not (mine did not). Jerks

Is the hydraulic pump at the same location for a 2013 Mercedes gl450?? I’m having a hard time finding it, and I’ve gone through the steps in the video already.

my power steering is hard and i just bought a replacement and still hard to drive .... i am confused

Great 👍

Did you every find the leak?, thanks for posting. Just bought ML with problem hatch... it will close but not open.

Hi, my power lift gate does not operate at all, it beeps though when I press open. Also the red light in the open/close does not light. Any idea what's wrong?

Does anyone know where this pump is located in the same year R class?

So was the gate not closing or opening before you added hydrulic fluid? What was the cause that led you to check that particular pump, thanks in advanced.

What is that Bosch thing for, level?

What was the problem that led to this?

What fluid has gone in

I am surprised to see that MB did not make access possible only from under the trunk just to make it more difficult to fill oil. Oil does not evaporate, yet could not see a trace of leaked oil, so where does the leaked oil !