Auto open boot conversion to manual opening?

[Nod]

Have auto open on my s211 2004 Estate that is somewhat temperamental and sometimes slams shut. I tried topping up the hydraulic fluid on the pump to no avail and do not want to go to the trouble to remove all the headliner to get to the worn out struts, which I think is the issue.

I understand the two inner struts open the boot (hydraulically by pump) and the two outer ones close it?

I have two s211's same year, same model (E320), one of them has the manual opening and this one has the auto open, think the manual opening is far better and the trunk slamming on the other one is becoming an issue.

Would it be possible to fit the manual open struts (stronger force, so the boot stays open) and do away with the inner struts or disconnect them and unplug the pump, does anyone know?

 

[Larkone]

I would be checking that the fittings and fitting locations are the same between the two cars so you could fit the manual struts to the auto opener tailgate. Luckily you have both so you could check.

 

[Snake Charmer]

My S211 shuts with a bit of a bang, one of those jobs on the toodoo list. I see the hinges have one cylinder connection to each hinge, the right hand is smaller diameter so I presume the left is hydraulic.

 

[Nod]

I would be checking that the fittings and fitting locations are the same between the two cars so you could fit the manual struts to the auto opener tailgate. Luckily you have both so you could check.

Yes- they look exactly the same, the manual open has just the x2 struts connected on the outer balljoints, whilst the auto has x4 connected, the inner ones being the struts that open boot aided by the hydraulic pump I think.
So am thinking of getting x2 manual open struts and fitting them in place of the outer ones that are on there. The auto open ones are 1300N of force and the manual ones are 1500N (or 1550N if no external spring). I will just unplug the hydraulic pump to stop it trying to open the boot and inspect the two inner struts to see if it will open with them still connected or if I have to try and get them off, or at least one end anyway.

Pain in the neck IMO the auto opening, more trouble than its worth and a pig to fix if it inevitably goes wrong!

 

[Nod]

My S211 shuts with a bit of a bang, one of those jobs on the toodoo list. I see the hinges have one cylinder connection to each hinge, the right hand is smaller diameter so I presume the left is hydraulic.

Yes, its a pain, I will have a closer look later at both the auto open and manual open, maybe take some pics of both and post them.
Have you thought of converting yours to manual opening?

You can also check the hydraulic fluid reservoir attached to the pump, sometimes it runs low and causes issues. In my case topping it up made no difference, think my struts have had it and as said think the only way to change the inner struts (boot opening) is to take all the headliner out to get to them, nightmare. The manual struts can be changed without doing this and look far simpler, hence me wanting to convert the auto one to a manual.

 

[Snake Charmer]

Have you thought of converting yours to manual opening?

No, I like the feature now the close button is working correctly. The hinges look like forgings and the ball ends look similar diameters so my first thought is the manual dampers are a swap. Not sure about the soft close working without the coding being changed but pulling the tailgate down by hand the closer does its job.

 

[Snake Charmer]

I have started to look deeper into this myself as the option to install a reversing camera has arisen.
From what I see on the parts diagram, the hydraulic tailgate has the cylinder on the l/h hinge and a potentiometer cylinder on r/h. I was thinking the potentiometer may faulty on mine allowing the hydraulic cylinder to drop the last part.
I did a couple of tests this afternoon stopping the tailgate at different positions by pressing the close button as an emergency stop and now wonder if the cylinder is worn or simply needs bleeding. Initial thoughts on bleeding might mean getting the cylinder out and lower than the pump or cracking the line open not something I would like to do inside the car.

Don't quote me, looking at the parts diagram the manual tailgate looks to have a sprung loaded gas ram on each hinge, if the ball ends are the same dianeter then a swap may be possible. The close mechanism might pose a problem and need coding out, also the lock may need changing if the manual tailgate does not lock electrically.

 

[Snake Charmer]

Missed this double jointed git when I last looked!! I can see moisture on the right cylinder so quite likely the gas has gone too.

From a bit of Googlefoo, these seem accessible without headlining removal through the dog guard roof clip. Gynaecological skills may be required.

890 SA code A2119801364 A2119801464


EDIT.

The MB parts catalogue schematic shows one gas cylinder on the left hinge numbered 60 that looks like a substitute for the hydraulic cylinder, it is in fact two additional gas cylinders. I double checked and found this one lurking on the other double jointed hinge.

From £9 each on Autodoc if you ignore their suggestions. Should be great for a week at £20 a pair!

 

[Nod]

I think the headliner has to be removed to replace the inner struts One of the struts has a double cable connected to it from the hydraulic pump and is in the way preventing removal, unless the headliner is dropped. The two outer struts can be changed over with careful precision maneuvering skills but it is the inner ones (that open the boot) that are the problem to change.

 

[Snake Charmer]

I think you are correct, I will get a pair of gas struts for mine.

 

[Snake Charmer]

Bought new struts from Autodoc, £47.02 a pair. Stabilus Lift-o-mat 1300N as per the original Mercedes units. Not the easiest job to replace but they pop on the pivot balls easier than they come off. I did it without dropping the headlining, just partially pulling it aside and removed the old gas struts past the hinges. The tailgate is much more controlled up and down, nothing like the thud it was previously when closing. I will try changing the hydraulic cylinder oil and bleeding to see if any further improvements can be made.

 

[Nod]

Bought new struts from Autodoc, £47.02 a pair. Stabilus Lift-o-mat 1300N as per the original Mercedes units. Not the easiest job to replace but they pop on the pivot balls easier than they come off. I did it without dropping the headlining, just partially pulling it aside and removed the old gas struts past the hinges. The tailgate is much more controlled up and down, nothing like the thud it was previously when closing. I will try changing the hydraulic cylinder oil and bleeding to see if any further improvements can be made.

Wow- well done, without having to remove the headlining....
Are these the inner or outer struts you replaced? The inner ones(think deal with opening more) have the cable connected to them and seems these are the ones people complain about changing. The outer ones I think are easier to change and are the closing struts. I guess all four though sort of 'work in unison', when the thing is being opened and closed somewhat?

I think it is the inner ones(opening I think) that have gone on mine but also it does not hold itself up very well and only lasts about 1 minute before the boot starts dropping down gradually. I may still go down the route of trying to convert it to a manual opener when I get round to it or the problem gets so bad that I have to.

When topping the hydraulic fluid up, you may find you have a sealed reservoir or hopefully one can be topped up by undoing a bolt that seals it. Word of caution though, be careful not to overfill it, as I did mine and when its shut the fluid returns mainly to the reservoir and can overflow it. There is a level mark on the unit, would not fill it beyond the mark to be safe, I did and it leaked. On mine seems changing the fluid did not improve things but have heard some people got a result. I had a sealed reservior and carefully drilled a filling hole then sealed it back up.