In my 'shop today, W176 with a pond inside...

[Bashir]

Some points to note if you fancy a go yourself. The hardest part is rear bumper removal. First off remove the rear lamps. They are held with a plastic wing-nut type affair...

Then the centre plastic trim that covers the boot striker needs to come out. Remove the two luggage hooks, the centre bolt and then it levers up off of six plastic clips...

With that out the way you can remove two grommets to reveal a couple of 10mm nuts run down very long guide pins. You need a rediculously deep socket, but I use a regular deep socket and a croc nose mole grip...

Then you have four acme type bolts, one each side where the bumper meets the rear quarter panel, then yank the bumper outwards from plastic guide it sits in.

And two underneath near the exhaust tailpipes...

Six push pin rivets hold the arch liner to the bumper, three each side

And then probably the trickiest bit. The bumper cover is clipped into the black bumper reinforcer each side, just below where the rear lamp fits. It needs teasing out. I have a nice wedge trim tool thing that does the trick...

Hi Thanks for the comprehensive reply, will follow and hopefully resolve. Much appreciated specially the level of detail.

 

[Blobcat]

Could one of the mods maybe put this in the diy section? Now the search function seems poor I have personally referenced this thread a few times for enquiries. If it was in the diy section it might be found more easily.

If of course it is good enough

I humbly request

I will copy it to the DIY section and put a link back to this thread for comments on the Bodywork section

We’ve not had that many “how to’s” recently so whilst we’re scrapping the barrel I think this just passes the new low water mark for inclusion

 

[Uncle Benz]

I will copy it to the DIY section and put a link back to this thread for comments on the Bodywork section

We’ve not had that many “how to’s” recently so whilst we’re scrapping the barrel I think this just passes the new low water mark for inclusion

Thank you! I'll try harder next time. I do so many common jobs that I should keep a camera to hand and document them.

 

[Blobcat]

Thank you! I'll try harder next time. I do so many common jobs that I should keep a camera to hand and document them.

If only you’d concentrate on other people’s work more than your own...

(or something like that used to be written on my reports...)

Much appreciate your write up, it’s information like this garnered from a professional in the field that really helps the forum.

 

[Blobcat]

Now copied into the DIY section here

 

[00slk]

Nice write up Uncle Benz
I wish I could stop the water leak on my r230 was fine until it leaked, dealt to it and fix the problem. Only it has started to leak again after a year or so, so reapplied the Malcolm method only for it to be worse than ever Still wringing out the towels is better than the PSE sponge soaking up the water.

 

[Flyinspanner]

Rather than buying new vents, wouldn’t this work as well if you just scraped off the old yellow seal and just put a nice fat bead of sealer around the old one?

 

[Uncle Benz]

You possibly could. The old seal is rubbery and keeps the vent in tension against the clips. Without it it would be free to rattle a bit. Might make it tricky to hold it squarely in place while the sealant dries. New vents are about £12 a go, so not bank breaking. The old rubbers are often mouldy and weak.

 

[Alan Forster]

Great write up and descriptions, have a virtual pint!

Does this effect the GLA do you know?

Hi, I have a 66 plate GLA 250 4Matic Premium Plus that has only done 17500 miles. A water leak has been driving me mad as I could not identify the cause. I thought that it was the sunroof.
I took the car to the main dealer in Bolton UK, Marshalls and they told me it was the vents. They said that the cost of repair was 8/10 hours labour at £160 per hour plus parts including new carpets circa £2k plus.
They said that Mercedes will not help as the car is out of warranty.
Sad!
Alan F
Bolton UK

 

[davemercedes]

If only you’d concentrate on other people’s work more than your own...

(or something like that used to be written on my reports...)

Much appreciate your write up, it’s information like this garnered from a professional in the field that really helps the forum.

+1
- Many thanks, for a concise and illustrated write-up Uncle Benz! I get worried now reading some of these fixes as Old Father Time is catching up on my S203 - it's a 2007 car so I start to worry what ponds etc I haven't found (even though there's nothing to suggest problems like this may be lurking inside!

 

[John Laidlaw]

Great write up, I'm sure there will be a GLA along soon also with the problem.....wait....

 

[John Laidlaw]

Hi, I have a 66 plate GLA 250 4Matic Premium Plus that has only done 17500 miles. A water leak has been driving me mad as I could not identify the cause. I thought that it was the sunroof.
I took the car to the main dealer in Bolton UK, Marshalls and they told me it was the vents. They said that the cost of repair was 8/10 hours labour at £160 per hour plus parts including new carpets circa £2k plus.
They said that Mercedes will not help as the car is out of warranty.
Sad!
Alan F
Bolton UK

You may have a solution now....

 

[MBW176]

I came across your explanation whilst Googling for a solution to this issue. Excellent explanation of what is needed Uncle.
I need to tackle this having just found that I have my own inside pool.

Can you please let me know the length of the 10mm socket wrench needed? I need to buy one for the job.

Are the bumpers more brittle in the cold? I'm nervous about the force needed to unclip and re-fix the bumpers but it has to be done outside and i'm afraid it's brass monkey weather right now.

Does it matter whether I use part A1698300342 or A1766302700?

 

[Uncle Benz]

The bumper may be slightly more brittle when cold, but it's pretty tough plastic. You'll get a feel for it. I've not managed to tear one yet. The depth of the 10mm socket, the pin that you need to reach down over must be about 100mm in length. I have some deep sockets, but not one that deep. My mole grip method works - the nuts are not very tight at all. Barely more than finger tight.

 

[MBW176]

The bumper may be slightly more brittle when cold, but it's pretty tough plastic. You'll get a feel for it. I've not managed to tear one yet. The depth of the 10mm socket, the pin that you need to reach down over must be about 100mm in length. I have some deep sockets, but not one that deep. My mole grip method works - the nuts are not very tight at all. Barely more than finger tight.

Thank you Uncle; very much appreciated.

 

[DREAMER NO2]

Thank you Huncle Benz Admin Any chance this W176 post can be keept as a sticky

 

[Blobcat]

Thank you Huncle Benz Admin Any chance this W176 post can be keept as a sticky

See post #25 above

 

[Timpar]

Some points to note if you fancy a go yourself. The hardest part is rear bumper removal. First off remove the rear lamps. They are held with a plastic wing-nut type affair...

Then the centre plastic trim that covers the boot striker needs to come out. Remove the two luggage hooks, the centre bolt and then it levers up off of six plastic clips...

With that out the way you can remove two grommets to reveal a couple of 10mm nuts run down very long guide pins. You need a rediculously deep socket, but I use a regular deep socket and a croc nose mole grip...

Then you have four acme type bolts, one each side where the bumper meets the rear quarter panel, then yank the bumper outwards from plastic guide it sits in.

And two underneath near the exhaust tailpipes...

Six push pin rivets hold the arch liner to the bumper, three each side

And then probably the trickiest bit. The bumper cover is clipped into the black bumper reinforcer each side, just below where the rear lamp fits. It needs teasing out. I have a nice wedge trim tool thing that does the trick...

Don't forget to unplug the parktronic sensors if fitted. Lay out an old blanket for the bumper to save marking the paint.

 

[Timpar]

Great help thank you! Having followed your instructions, I have wet vacuumed the water from the foot well, every time I drive the car its filling back with water? I vacuun the water and after a short dry road drive it's filled again? Where can I vacuum the water from beside the carpet? Presumably there's a lake gathering somewhere in the car?

 

[Blobcat]

Great help thank you! Having followed your instructions, I have wet vacuumed the water from the foot well, every time I drive the car its filling back with water? I vacuun the water and after a short dry road drive it's filled again? Where can I vacuum the water from beside the carpet? Presumably there's a lake gathering somewhere in the car?

Have you followed the guide and stopped the water getting in?