Td5 D2 bodywork - Door window Rust

All the recent work re-spraying the offside door panels provided a good opportunity to do other work to the door internals. This post concerns the work done to both of the rear passenger quarter-light window frames.

When my ownership began (roughly 4 years ago), I noticed a little rusty patch on the base of the quarter-light frames just above the door panels. It was roughly the same on both sides of the vehicle, so I just kind of 'logged it' as I got in and out over the years. Looking at similar aged examples made me realise that it is a common rust area.  

Well, over time, it never really bothered me and there was no real urge to address it given the state of the door panel paint finish...

Some time last year when I was fitting the new speakers to the rear door panels I became aware, while repeatedly operating the door, of hearing bits of stuff falling off inside the door body and falling into the bottom of the door. This was apparent on both of the rear doors. Immediately I thought it has to be connected to that rusty area and as usual with corrosion it is the bits you don't see that cause the problems.

At that point in the proceedings I had not seen inside the door or even removed the internal door-card panel. Rave and the net were consulted and things got moving... but slowly..

Here is a photo from the net that basically sums the situation up..

This image shows the quarter-light frame partially removed from the door body to reveal the extent of the hidden corrosion and the possibility that the quarter-light glass will fall out of its corroded frame.

The horizontal green-ish line on the glass surface represents the fitted position inside the door body and were the sealing rubber contacts the glass. In the above image the sealing rubber strip has already been removed. 

This is the same area on Hx with the sealing strip removed. This is taken from the outside and shows the extent of the corrosion that has been visible on the vertical frame for years. The quarter-light glass and it's frame remain bolted to the door body

This view is from the inside of the door with the door-card and the internal sealing strip removed. That black toggle shaped thing is the internal door lock button and the grey crinkly sheet is what remained of the vapor barrier. I quite like the colours in this image, the sun was just in the right position to highlight all that crusty corrosion..

Another view from the outside trying to show the corrosion on the bottom frame of the quarter-light. I believe this shot was taken after I had cleaned and cleared the area a bit prior to treatment.

The 'treatment' that I choose was to clean up the corroded areas and treat them with Kurust followed by a thick coating of black Hammerite which can be seen in the above photos. The strips of masking tape helped to protect the surrounding areas from paint spills 

Viewed from the internal side of the door.. Unfortunately, the black paint does not show up too well in a photo..

These last two photos show the same area, but on the nearside rear door. The last photo clearly shows the u-shaped trough that the glass pane sits in being in a good condition with the least amount of corrosion present. 

Tried to understand how this area could become so corroded. I reckon the very shape of that 'trough' allows rain water to pool in it and do its stuff over time hidden from view.

The outside rubber sealing strip is a snug fit to the glass in general, but all the same some water probably gets by and reaches the trough. More telling is the fact that the sealing strip does not make a good 'seal' around the vertical frame and much more water will find its way in through that gap.

The solution is to run some silicone sealer into that vertical gap and along the horizontal glass seal. Plan to do just that once the respraying of the outer panel is completed as the sealer strip and door handles will be removed again to facilitate the spraying and buffing.

Meant to say that all the flaky bits of corroded metal heard falling into the bottom of the doors were easily removed with a magnet on a piece of garden wire.