I had a good look at the exposed wooden frame which is as good as new, same colour as new stuff and no hint of damp so that's one less wall to worry about! Not bad for a 29 year old van. I also noticed at the time of the window removal that the original sealant was still in a tacky state which meant it was still working; in fact it was a bit tricky prying out the frame away from the sealant.

The aluminium frame is screwed together so it is a simple case of removing the screws, I made a diagram of what went where as I stripped it down to make it easier during reconstruction. I recommend Wearing gloves while removing the glass shards. You will also need to take care as there is a plastic edge strip around the original glass which you will need when putting in the Plexiglas sheet to make it fit better.

Once all the old sealant and broken glass was removed I made up a template with cardboard in order to get the correct size to cut the 4mm Plexiglas to. Plexiglas is easily cut with a fine-bladed jig-saw and any minor adjustments can be done with a wood plane, I sandwiched the Plexiglas between two pieces of wood in order to help protect it.

Now I had all the parts ready for reassembly I did a dry fit first, it all went together well and looked good, one thing I forgot to allow for is the 1mm bead of silicon I was going to fit around the inside of the frame, unfortunately it was after I put the silicon in and tried to rebuild it all that I discovered this so had to disassemble the whole lot again, remove the Plexiglas and shave off a mm all round, please bare this in mind if you have not got the original seal strip, and don't follow my mistake!

Anyone working on these old glass windows with alloy frames remember that the frame with glass in is quite heavy and it takes two of you to pull it off the original mastic, which in this case was still very sticky and flexible, proof of how well constructed these vans where!
I used 4mm thick Bayer Toughened safety glass, vandal proof according to the local glazier. A sheet of 1ft x 2ft cost me £12 which I thought was OK.

Unfortunately in this case the glass edging strip was past repair/use so I had to resort to using the sealant gun, not one of my favourite tools!

Still plenty of work needing doing to the van including a good wash and repair to paintwork.