E61 tailgate pump leak repair

[myles]

This is my experience in trying to fix a problem with my tailgate pump leaking. Use this information at your own risk. etc.etc.etc.

My auto tailgate hydraulic pump was leaking from the square plate beside the reservoir. It was otherwise working ok. The leak was so bad that it was leaving puddles on the garage floor after leaking out of the car.

Inkeds-l1600_LI.jpg

I took it all out of the car and started to pull it apart. I undid the 4 screws that hold the plate on the base. Inside the plate was a chamber that held a piston with a double return spring. It appeared that the piston seal was leaking and allowing hydraulic fluid into the lower part of the chamber.
20161027_140025.jpg20161027_140050.jpg

It wasn't necessary, but I also separated the left and right half. This enabled me to replace some of the smaller o-rings between two sides.
20161027_140059.jpg

I was able to find a suitable replacement seal for the piston. It was mineral hydraulic fluid compatible but not quite high enough to fit the grove in the piston completely, so I had to add a backup spacer to make it a better fit. The seal is a nitrile type and has an internal diameter of 35mm, and outer diameter of 45mm and a height of 6 - 6.6mm. The spacer is PTFE 35.4mm ID, 39.8mm OD, 1.25mm high. The spacer was cut open to be able to fit into the grove on the piston and carefully placed above the seal in the piston groove.

The other o-rings that I replaced were (1x) 9mm x 2mm and (5x) 0.145" x 0.070" all nitrile type. The 5 smaller o-rings went in between the left and right sections of the assembly and the single larger o-ring replaced the seal on this thing (I'm not sure if it's a solenoid or pressure sensor).

20161027_140148.jpg

Parts cost less than AU$50 and the repair took a few hours. This has worked for over a year now and hopefully this helps someone else.

[pbonsalb]

Great job. This is a common and potentially very expensive problem as the wagons age. We were lucky the dealer replaced our pump and harness under extended warranty just before it expired.

[DaHose]

This looks like a best possible outcome! If I understand fully, the correct seal is 35mm ID, 45mm OD, and 7.5mm thick. It also sounds like this repair could be done in the car.

Nice job.

Jose

[myles]

I've just grabbed the old seal. The measurements are difficult to take because the inner and outer surfaces aren't square. The piston is the best part to take the measurements from and mine is back where it belongs, so can't look at it. I can say that the old one is 6.85mm in height. If you're looking at doing this, I'd definitely recommend taking it apart and taking the piston, the chamber and old seal with you to your local seal supplier. https://www.ludowiciseals.com.au/ were very helpful for me. The measurements that I've written earlier are the specs of the new seals as written up on the invoice.

[pbonsalb]

I found this link in case anyone wants to convert from power tailgate to manual tailgate.

http://www.bimmerfest.com/forums/sho.../774852?page=2

[WhiteSpot™]

Thanks for this info myles . This is the information I was looking.

I have a E61 LCI and in January 2016 I have to put some oil in the reservoir of the pump, and in July 2017 I have to put again.
Now in August 2019 the reservoir is again empty and the last time I decided to put some absorbent paper around the pipes /lines and under the pump to see where is the leaking.
The absorbent papper around the lines are dry and with no signs of oil leakage but in bottom of the pump is completely soak in oil as you can see in the photos.




I will try to remove the bottom of the pump to change the seal / o-ring of the pump. When the job is done i´ll come back to tell the results. I hope here in Portugal be able to found easily the seal / o-ring.

[WhiteSpot™]

Job done.

I find a almost exact o-ring replacement (the one in the left in the photo whit the two o-ring).

It cost me 2.20€ in a specialized shop here in Oporto - Portugal.

The rest of the images are self explanatory.








Only to clarify, this is a January 2009 E61 LCI 535D. I bought it in January 2015 if I not wrong. In this time I have replaced the missing oil 3 times. I barely use the car and the trunk a lot less (one time per month or less).

I have bought two o-ring just in case for a future need. Is a lot easier to have a replacement than to have to purchase something that can be not found again.

I hope it help someone else as it help me.

Thanks again for this @myles.

[DaHose]

What is the part number for that seal? I want to order one up.

Jose

[WhiteSpot™]

What is the part number for that seal? I want to order one up.

Jose

Sorry for the late reply. There is no part number for the seal / o-ring. bought one in a specialized shop (sealant´s and o-ring´s) in Oporto - Portugal.

[Halr]

This was a great thread and helped me immensely with rebuilding my own pump so I thank you Myles and WhiteSpot for originally posting this..

I was not content to just refill fluid every year so I ended up removing the pump and went looking for the proper seal replacement. I am happy to report that I finally found a supplier online that sells the proper seal for about $16 plus shipping. I have installed the new seal which is slightly firmer than the original seal I removed, but that may have just gotten soft with age. The replacement seal looks IDENTICAL to the original seal and does not require any spacers like the one mentioned above. The only thing I would caution anyone trying to do this replacement is to be prepared to fight getting that top 10mm bolt back into the pump bracket. Not hard to take out, but a PITA to put back in! Good luck with this repair. Really easy to replace the seal. I did not replace O-rings as they did not appear to leak. I only opened the 4 screws at the bottom of the piston chamber, removed the springs and piston, and then just put it back together. Simple! I also just emptied the fluid using the screw at the bottom and then refilled with fresh fluid after getting all debris out. (You have to get the pump upside down to refill so it does mean removing the bracket assembly)

Metric Seals Incorporated
17030 Westfield Park Road
Westfield, IN 46074
Ph (317) 896-3555
metricsealsinc.com

Part number needed for this pump: Item: N 45 x 35 x 7 C2 Part # C24035N3584

This URL will get you directly to the site for this seal:

https://www.metricsealsinc.com/c24035n3584-n-45-x-35-x-7-c2

[WhiteSpot™]

Thanks Halr and I'm glad that my posting here help you somehow to solve your leaking pump.

To clarify the OP was myles, and I only add my "story" to his post, so all the merit should be directed to myles.

[adonnan]

I am experiencing two issues. With the pump disconnected I can’t manually close the lift gate. I also can’t get that plunger out of the pump housing. It’s pretty stuck. Ideas? Already bought the seal to replace on plunger.

[Gman6262]

I am experiencing two issues. With the pump disconnected I can’t manually close the lift gate. I also can’t get that plunger out of the pump housing. It’s pretty stuck. Ideas? Already bought the seal to replace on plunger.

To get the piston out of the accumulator bore, you need to split the pump side of the assembly from the accumulator / valve body side. There are two hex head cap screws that hold the two halves together. This releases the hydrostatic lock, and you'll be able to remove the piston. I've just completed a short writeup of my hydraulic pump rebuild here: https://www.fightchaos.com/2020/09/b...p-rebuild.html

[d3adly]

Hello guys, I know it's been a while but I just got this problem too. I added an oil to the system, as it was completely down to 0 (and it was like that for a year). Then it started working okay for 1 day and after that, when I open the tailgate it start closing itself really slow, and in period of 20 seconds it is completely closed. What should I check ? All the O-rings looked okay. The old seal is looking fine (even creating a vacuum). The right gas suspension is a new (bought it 3 months ago). Also, if I disconnect the 2 hydro hoses from the pump, the tailgate won't close itself.

Thanks in advance!

[d3adly]

Hello guys, I know it's been a while but I just got this problem too. I added an oil to the system, as it was completely down to 0 (and it was like that for a year). Then it started working okay for 1 day and after that, when I open the tailgate it start closing itself really slow, and in period of 20 seconds it is completely closed. What should I check ? All the O-rings looked okay. The old seal is looking fine (even creating a vacuum). The right gas suspension is a new (bought it 3 months ago). Also, if I disconnect the 2 hydro hoses from the pump, the tailgate won't close itself.

Thanks in advance!

Resolved: The issue was in the oil. I put an ATF one and now it works perfect.