Leaking roof or rear lights? GL 420

[dannyoow]

Good evening all,

So I had my rear SAM fail due to water ingress.

Got my new unit and wanting to prevent it happening again, put an open hose on the roof and after 3 minutes I had drips into the rear where the sam sits (its currently temp fixed in the boot) so suspect either roof attachment bolts securing the glass/plastic panel or its travelling down past into the boot drainage.

I have some rear light seals on order and will switch them out, going to order a boot seal as well just for good measure but has anyone successfully resealed the glass/plastic roof at the rear on these?

Or have had a similar experience and found it to be something else entirely?

Just wanting to get this fixed and rolling before Christmas with no more water ingress!

Thanks in advance

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[brandwooddixon]

Do you have a sunroof?
All sunroofs leak to an extent, they are reliant on drainage channels and pipework to prevent water ingress into the car. There tends to be a channel down each A and C pillar i.e., four.
Often, they can be cleaned using long lengths of net curtain wire.

That said you may have only been playing the water over a section of the car roof that doesn't have a sunroof.
Other suspect points - mounting point for boot strut.

In any case with water, it's best to work on preventing it from getting in but allow for ingress and ensure that it can get out. Thus, if resealing lights leave a gap at the bottom so that it can escape.

Thinking about it I'm sure that there's an issue on one of the SUV type, MBs whereby a body vent behind the bumper/back light has issues of water ingress.
I'm sure that its been posted on these forums somewhere

 

[mioba]

Id be checking all the drains are clear. You will see water marks on the door seal if is that.
chuck some talc about inside if possible and you will see the streaking and hopefully find the leak.
Mercs are usually very good in terms of deign and keeping water out.