bigjontpa

Good morning all,

Recently, my 2008 550SL has been giving me trouble with the trunk. When I have occasion to open the trunk, it will not fully close. I will press the appropriate button to close it, and it closes- but it does not close 100%. It closes- but does not seem to latch and there is about 1/4 inch of play in the trunk lid. When I get into the car- it alerts me that the trunk is not closed.

As a result, I have to open it again, and physically/manually close it with a bit of force to make sure it latches. I don't believe this can be good for the hydraulics. I have checked the hardware, and nothing appears to be loose or worn.

I have this issue with both the top up and the top stowed. Any ideas here on what I can do besides spending hundreds at the shop?

Your feedback is welcomed and appreciated.

JVN

Aussiesuede

See the sticky at the top of the page - Trunk soft close issues. You should find a solution there.

bigjontpa

Thanks, I gave it a look and will give it a try when I have the time. I have a pretty expensive warranty on the car, too (for fear of hydraulic problems) so I'll look to see if it can be covered by warranty. Worth a shot. Appreciate your reply.

bobterry99

You may have an air leak in the latch mechanism, or the rotary latch for the trunk lid is no signaling the pump to lock the trunk down tight.

To investigate, I would first reset the pneumatic (PSE) pump by briefly interrupting power to it. Many years ago I identified the fuse to pull, and more recently Rodney (a.k.a. "Rudeney" did so as well.) I always pull the fuse, but I presume disconnecting the battery for a couple of minutes would perform the reset as well.

Next I would open the trunk lid and push on the rotary latch to simulate the effect of the trunk lid being in the intermediate-closed position. If the switch and the pump are fine, then you should hear the pump run and suck the rotary latch into its fully locked position. You can restore the latch to its fully-open position by pressing the green emergency release button located in the trunk.

If you invest $300 in a Chinese-clone-based Star Diagnosis System the above evaluation can be done effortlessly via keystrokes from a laptop PC.

bigjontpa

Thanks for your feedback. I'll give this a look as well.

JVN

A1EK

I had this issue, my car somehow got confused when I close the trunk too quick. I just needed to reset the system.

kemzo

I have this same issue but I don’t think I can fix this by myself...

You Tube

Ghostty

I'd say to fix the latch air leak you're looking at about a 2-3 out of 10 difficulty. If you're carefull and have fixed in the past minor things - this is not a problem at all.

Or you can go through the safe side and order a new latch at the dealer - if I remember correctly the latch is about $300-400. They cam replace it for you as well, for extra $$ of course.

Regards

fun33

Had the exact same problem with my brand new 2018 S560. Fortunately, for me, the dealer replaced it under warranty. Really inexcusable that MB has continued to install this same inferior lock design year after year.

bobterry99

In the video I see someone operating the trunk release handle to open the lock, but the lock is already open.

kemzo

Yes, it’s mainly for the leaking air sound. I’ve purchased the glue and ready but I’m stuck in taking it out?

kemzo

Got it!
found only one leak...

gregorynp

I had the same problem. Had to replace the part that sucks the trunk closed. About $350 for the part

kemzo

Just fixed mine for the grand total of $5 for epoxy glue.

A1EK

[QUOTE=kemzo;7763747]Just fixed mine for the grand total of $5 for epoxy glue.[/QUOT

Glad you fixed it, what epoxy glue did you buy?

I think I have a leak in my lock, as I have to disconnect and reset my trunk / boot battery often. Once I disconnect the battery and re-connect the soft close works again.

What do you think?

Frederick NL

Same issue for sure. Until you fix it you’d be better of by pulling the fuse concerned. Fuse box behind right seat, forgot the number, but you’ll easily find it on the forum.

A1EK

Thanks,. Anyone know the correct fuse to pull?!

Rudeney

Fuse 71, unless you have the MY2009+ facelift, then it's fuse 54.

Frederick NL

*sigh* don’t tell me you need a fuse chart now

http://benzbits.com/R230/Fuses/RearFuses/

A1EK

Thanks Rudney, I take it, it's behind drivers seat?

A1EK

No I do not a fuse chart, working off my phone sometimes just asking is easier!

kemzo

You will be better off fixing it than relying pulling fuse every time, especially in these cars. And it doesn’t last, mine only last for about 4-5 openings and closings. As for the type of glue, I just went to NAPA and ask for the strongest rubber epoxy that’s in gel form for easy application. The one I bought, bond in 5 minutes and cures in an hour. I will get the name when I get to my car.

A1EK

Okay so took your advice and now permanently fixed the soft close issue.

Took a bit of looking but found that the upper tube with the ball bearing had a tiny crack, I used to some soap bubbles and found the air leaking.




Dried it all off, used some Plexus 300 Industrial epoxy that is mixed together and sets in 15mins.






No more leaks and the soft close is working better than before, as I hear the latching 'click' operate quicker, over the last couple of weeks this click has been getting slower and slower, then will stop soft closing all together until I pull the battery and reset.

Video of soft close removed:

Video of identifying leak:

Video of soft close now repaired:

All in with fault finding and allowing for epoxy to dry took about 45mins.

Thanks

Frederick NL

That was unbelievably fast. I want your urine tested for doping.

kemzo

Hahahaha! It’s so rewarding...