W164 Water Leak Rear Seal

[E55BOF]

Good evening all.

I have a water leak into the RH rear void below the rear SAM. (Haven't checked the LH void, but I will). My first thought was the rear light cluster, but that would presumably run down the bodywork below the cluster. That may be happening as well, of course, but...

My leak after the recent very heavy rain is dripping down clear of the fuse block on to the deflector plate above the SAM, so it must be free-falling vertically, not running down the inside of the bodywork . It must therefore be either the (fixed) rear side window, or the tailgate seal. (Incidentally, I'd swear the SAM is brand new, or nearly; it certainly hasn't been in there since 2007. It may be the rear light cluster seal has already been replaced).

I found this thread: ML W164 Leak from Tailgate | Bodywork

Lightbulb moment (I hope...)!. Fitting the rear view camera recently, I pulled the seal off to run the wiring across above the roof liner to get access, so it has been disturbed. There were traces of a yellowish-white sealant in places, whether from original assembly or not I do not know. Do I go for silicone sealant all round the seal (fill the groove up and refit the seal - very messy, difficult to get an even bead, and how much do I use?), or surgical tubing? I like the latter idea, but I've no idea what size and wall thickness to use, though there's plenty in many different sizes on eBay. Anybody know?

Thinks: I could perhaps use plumber's putty rather than a silicone sealant? I've no idea. No, tubing would be better.

The OP was on here last year, but has only five posts, so I cannot PM him to ask. Can the mods permit me to send him/her a message?

 

[E55BOF]

At the end of the day it was just the usual taillight cluster seal; the water was dripping from the lip of the bodywork cutaway on to the deflector plate, not running down on the inside. Silicon sealant around where the seal meets the metal , and the groove the cluster edge makes in that seal for good measure, seems to have done the trick. I've put a small towel in there, with a sheet of Kimwipe on top to provide a witness mark if it is still leaking, and will take a look after every rainy day for a while just to be sure, though.

 

[E55BOF]

Rained overnight; still leaking a bit; new gasket ordered from MB Newcastle.

I'll try one of the cheap 'n cheerful Chinese ones for the LH side, but that's less crucial; no SAM there.