Water Leak in Boot

[zoidberg444]

My poor car "Betty" seems to have sprung a leak. I noticed water collecting on the plastic trim panels behind the rear lights last year but it seemed to be fairly intermittent. Well its got worse to the point i've had to deal with it. It was soaking the carpet and the stuff in the boot.

I start disassembling everything, i suspected the rear light gaskets had perished and were leaking. I took them out and the weather strip off the roof and cleaned the mud and leafs out of everything but it was still leaking so i ripped out the plastic trim from the inside and had my dad spray the car with the hosepipe to try and find where it was leaking.




I found water leaking from out of what seam but i couldn't see how it was getting in there in the first place. So i took the weather strip out and found this.

Seems there was some stuff put in the seams under the boot seal but this stuff has perished or something.

Doesn't look in great condition. Near as i can tell the water must have been finding its way under the seal and getting into the gap in the seam and then running down the inside.

So has anyone had this before and what did you use to seal it up? Bog standard silicone sealer or did you use some proper seam sealer? I have heard sealing seams with water leaks on cars can be a bit of a pain.