I just used a run of the mill, adjustable 2" SS worm-drive clamp from my supplies bin to put the reservoir back on. This is a really easy fix to complete. The leaked oil will have turned really sticky, but you can remove it with some mineral spirits and paper towels.

Jose

 

Not sure I would want to do it again, but finally fixed the failing lift gate on the wagon.

I'd spent some time looking at other postings and had my bearings on what to do.


How to refill the liftgate pump on an E60 - Tailgate not opening fully

https://5series.net/forums/e61-touri...-137749/page4/

I'd ordered the AC-Delco 10-5041 tailgate hydraulic fluid last week, and had my turkey baster ready.

It was a pain to do, and I had to cut away some of the carpet to get up to the almost impossible to reach top bracket bolt. (The second link has a good picture of what to go looking for).

Hardest was having to judge how much fluid needed to go in. I just took a guess and filled it 3/4.

Anyway, seemed to work and with it all buttoned up she's as smooth as silk.

 

Why remove the pump? I found that it was incredibly easy to just pop off the reservoir, flush, refill and put the reservoir back on with the pump mounted.

Isn't it great how quiet and smoothly the gate opens when it has fresh oil? Beats $400 on a rebuild, or $800 on a new pump!

Jose

 

Thanks for your write up on this Jose. It saved me a lot of time and headache. My tailgate was inoperable for almost 6 months (due to lacking fluid) so I was just using the glass to access the hatch this whole time.

As of last night after a hydraulic refill its back to working perfectly.

One issue I had is with the ear clamp. For some reason I decided to rotate the clamp around perfectly so I couldn't access the crimped part

I ended up having to remove the two fasteners that hold the pump assembly down to rotate the clamp back to where I used sheet metal snips to cut the crimped junction off. After that everything was straightforward. The nylon cloth with channel locks to pull the reservoir down is pure genius!

 

i just fixed mine today with a quart of the Shell fluid from Amazon. The hatch was working 3/4 of the time and making a grinding noise. Sure enough, the fluid was low.

While it's true that the upper bolt is a pain to access, it is possible without removing any trim panels. I opened the door inside the cargo area, took out the bracket holding the sat radio tuner, pulled back the carpet, and was able to access all three bolts and remove the pump. It seems like many people just clip off the retaining clamp and use a worm-drive clamp as a replacement, but I wanted to try and access the factory fill plug on the bottom of the reservoir.

My biggest concern was trying to figure out why the fluid was low in the first place. It's a closed system so the fluid level shouldn't change over time, but I found sticky residue under the pump. I believe mine is leaking at the bottom of the pump housing.

edit: I should have mentioned, I have about 80% of the quart of fluid left over. I only needed about 100mL or so to flush and top off. If anyone needs a little, let me know.

 

I'm confused by this also. There was a little bit of fluid that had leaked but not as much that was missing from the reservoir. I'm guessing after enough cycles the fluid breaks down and starts to get thicker?

 

The sticky residue is hydraulic oil after all the volatile compounds have evaporated. So all the fluid that is missing actually did leak out.

You can clean up the sticky stuff with some mineral spirits. I have not had to look at my pump again since the refill, so any leakage is very slow. If I have to refill again, I am thinking of finding a spare pump and taking apart the top to see if the leak is just due to an easily replaced seal. If so, then we should be able to replace pump seals, AND refill without removing anything. That would be AWESOME!

Jose

 

Just wanted to share this with anyone who may find it useful.

I recently ran into the issue with my tailgate not performing as it should so like everyone else here I found
myself dismantling the left side interior of the rear, well lets be honest, it's more like 85% of the rear of my
530xi wagon. Went to my local auto parts store and they did not carry any of the 3 suggested hydraulic
fluids that I had read about.

1.) AC Delco 5041
2.) AeroShell 41
3.) Royco 782

The store manager suggested one I had not heard of however the container specifically stated it was for BMW's.
I bought it just because I'm kind of impatient and figured i would research it before using it and if it turned out
it would be adequate then I already had it and didn't have to wait any longer. Soon after looking up the fluid specs
I discovered that my car has been running with this as the designated power steering fluid the whole time which is
CHF 11S by Pentosin (in the green can). Even with that knowledge I STILL did not know if it was good enough for
the hydraulic pump because I could find NOTHING ANYWHERE in forums or other places. People seem to take
hydraulic fluids and fluids in general very seriously which is news to me because I don't know jack about any of this
stuff. Learning as I go. So I decided to go directly to the source and I sent an email Pentosin. The Brand Director,
Mark Malone responded promptly the same day and assured me the fluid would be fine if not better than fine for my
tailgates hydraulic pump. It is a commonly used fluid in German made convertible top cars also. And I can 100% agree
with that statement. This was in April of this year and my tailgate has ran smoother and quieter than it has before.

So, what I am getting at is, if you find yourself in this situation while owning a BMW and you already happen to have
CHF 11S in your garage you DO NOT need to go out and buy something else to fix this problem.Your power steering
fluid that is sitting on the shelf will do just fine if not better. CHF 11S is very similar in viscosity to the other recommended
fluids and like them is approved to be used in airplanes plus able to make the claim of being "super clean".The amount
needed to go into the hydraulic pump reservoir isn't much and you shouldn't fill it up to the top anyways. There is
a max fill line that you should stay below.

I don't know about everybody here but I'm not made of money and the cost to upkeep these cars can get up there quickly
when you run into a series of issues one after another which I have, 10 of them to be exact since buying this car used in August
of last year. This past month of June has been uneventful which tells me I better be prepared for something soon. Lol. It never ends!
Hopefully this saves a few people from spending money on something they may already have but don't know it.

Good Luck!

Pentosin CHF 11S Power steering fluid

 

as others have noted and as I have posted previously earlier in this thread, this top-up procedure can be accomplished without removing a lot of the trim panels. i topped up my fluid (very slow leak in my pump) last week and only removed:

-the left side 'door' in the trunk
-the rear-most floor panel (the one that folds up with the small strut and two cords)
-the satellite tuner and bracket it was attached to

that it. from there i could fold back the soft insulation material and reach the pump. the first two times i topped-up the fluid, i totally removed the pump by removing the three bolts and turning the pump upside down to fill it from the screw on the bottom of the reservoir. the bottom screws are easy to get to but the top one is a total PITA, but possible to reach.

for the refill this time, i decided to do what others have done and cut off the crimped on clamp securing the reservoir to the pump housing. this allows the reservoir to drop down just far enough to refill the fluid. i cycled the door a few times and then make sure it was completely topped up. I did not use a worm-drive hose clamp to secure the reservoir but instead used the same style crimp clamp that was OEM. i happened to have these laying around from another project:


and the small one in this kit (listed as "142mm-176mm(7mm)") was a perfect fit to secure the reservoir.

In the future, i will just dremel off the old clamp, put in some new fluid, and reclamp the reservoir. I could probably complete the whole process in 30 minutes or less from now on.

 

Has anyone tackled replacing the seals or the unit with a rebuilt one? My tailgate will crack open on its own, but not lift up at the initial attempt, but will continue opening on its own after a bit of manual assistance. Same result after refilling the unit.