28th December 2021 The pull down continues

 It was apparent that the DPO had put some time and effort into adding sealer of some sort around the inside of the boot and the front and rear glazing. I was a little confused as to why he would have sealed inside the boot thus preventing any water getting out???

As I mentioned previously it was very difficult to extract the rear screen.

I had to carefully cut away the "black stuff" which must have been windscreen sealer in a previous life to release the rubber. Strangely the rubber seals both front and back were soft and pliable, good enough to reuse after a wash. I worked around the boot removing as much of the BS (Black Stuff) as I could, then got to work on the rear window aperture. The BS was 5mm thick in some places and didn't want to let go. However I persevered using special tool KJ 285 (otherwise known as an old 1/2" wood chisel :-)  ) 

Now I could see what was going on  I finished the job off with a rotary wire brush and there before was the reason the seal was leaking,

Pictures of driver's side . First doesn't reveal the problem but with a light behind the panel all becomes clear in the second picture. The third being a closer view..

 The next few pictures shot show the rough finish on the seal lip.

This picture shows the left side of the rear seal. There had been a repair done in this area as well. The silver piece is the back of a 12' steel rule showing the 5 or 6 mm dip in this area. Again it prevents the seal doing the job it is there to do. This area will be reshaped and repaired to follow the bottom of the seal. This probably would not let water inside initially, but water pooling under the outside of the seal lip would cause a rust hole eventually.

The pointer shows the lumpy repair to the lip the boot seal fits over. This causes it to sit incorrectly and allows water inside.

It would seem that repairs had been made around the rear window at some point and the finish on those repairs was the primary cause of failure to seal. The welding was left very rough and the hole I discovered on the drivers side may have been full of welding slag and not noticed.
The seal would have not sealed correctly because the  lumpy welding would have spread it "open" in a few places. A little water ingress to unpainted welding and rust happened. Water runs inside boot and car.
Owner then applies seal around the rubber to stop this, but by now it is too late the damage is done. I am guessing after  the lack of success  in stopping it leaking a new seal was installed, but without removing all the old sealer. The problem continues until  the car gets disposed of as too hard.

This guesswork perhaps shows that when fixing problems with windscreen seals you first check that where it goes is clean and straight. It would seem that there were a few areas around the rear screen and the boot lid seal that had been welded up but left lumpy, thus preventing both seals doing the job they were designed for. A seal in good order correctly installed should keep water out without needing to apply several tubes of windscreen seal compound.

In the case of the obvious hole, it would never has sealed under the rubber.

I will tidy up the lip around the rear screen before trying to reinstall the rubber and glass.

Just because you can't see any of this when everything is in place does not mean it doesn't matter.

Also several areas where the boot lid seal fits need the same treatment.

Having done this I would suggest that both seals will work as intended keeping water outside without any additional sealer needed.

Much more work needed to get everything the correct shape