Mike Howles' guide to windscreen surround repair
Firstly, I must thank Andy Gray for hosting this info for a considerable length of timeAndy Gray's site.
Ok, the windscreen, well, what a mess.
A previous owner had attempted to seal the leaking screen by putting bathroom sealant between the glass and the sealing rubber. The real problem is (of course) that the windscreen surround is rusting away. Despite looking OK from the outside, it didn't require any effort to push a finger straight through the panel. The real damage becomes apparent when you strip the interior and take out the windscreen.
As you can see, the inner structure is only secure in one place. 50% of the left hand side, and 30% of the right hand side has gone completely. (This picture also shows the left hand headlamp shroud which was taken from the pick-up).
The object of the exercise is to cut a complete chunk out of the front panel and replace it with a sound one from another vehicle. I went down to see Bob at Wilts Aircooled and hacked the front off a 73 pick-up. (Spooky strikes again... I bought an engine lid at Vanfest which was blue and still had the registration plate on it. When we had cut the front off this pick-up, I cut out one of the headlights complete with surrounding skin and noticed the front number plate... guess what, only the same as the one hanging in the garage at home....Spooky now has the front and back of a pick-up!!!) This was the easy bit, I cut off about half-way up the A-pillars at the top end (the higher up the better really as it gives you more to mess about with), the bottom is cut along a line running across the top of the front intake grille, this is an area where all three of the skins come together: a) the front panel, b) the intake plenum top lip, and c) the inner structure bottom lip. Do the same with the one to be replaced except cut as high up as you dare along the bottom cut and as low as you dare across the windscreen pillars, this gives more to play with.
It is probably essential to strip out the interior from the front of the van. The windscreen comes out very easily, so watch you don't pop it out right onto the floor. Now is a good time to clean up the top of the surround, and repair any other corrosion. You need to peel back the head lining on the left of the cab to withdraw the interior light wiring from the left hand windscreen pillar before you cut it.
Something we didn't do, but which would assist people in the future, would be to weld bracing rods across the door apertures prior to cutting the old section out. This is not absolutely necessary as we found that the frame moved about 1mm and was easily taken up when fitting the new piece. At least make measurements along A-A and B-B to check when fitting the new part.
MOST IMPORTANT! The most crucial measurement of the whole exercise: The operation depends on maintaining the distance between the two dashboard mounting anchor nuts. I made two brackets with close tolerance holes that would fit on both sides. These were used to position the new part during fitting and eventual welding.
The picture above shows the left hand side bracket in place during the welding process, this is only because I did not take a picture of the manufacture of these brackets. You MUST make these brackets up BEFORE you start cutting out the old surround, I cannot stress this enough because if you don't then bar using the dashboard at a template there will be no way of getting the new surround in the right place.
The job is much easier with an assistant (this is my father). The cutting line across the front panel can be seen clearly. We used two 4.5 inch angle grinders (my father brought his down with him), it is not possible to cut completely through the A-pillars with a 4.5 inch but it can be finished with a hacksaw. (When I cut the one out of the pick-up Bob at West Wilts Aircooled kindly lent me his monster 9 inch which made the job very quick and easy.)
When cutting the front ensure that the cut is horizontal right along the length of the front panel. The cuts should be made at an angle across the windscreen pillars, so that the new part can be easily moved into position whilst it is being trimmed to shape:
The point of no return!
The following pictures show the 'hole' from inside & out.
Now comes the time consuming part: getting the 'new' section small enough, and the 'hole' big enough so that everything fits neatly. I cannot stress enough that time taken over this stage could save a lot of grief later. Once the new section is a reasonable fit, it can be secured in place and tack welded. With my van, the fit wasn't absolutely perfect; it was about 1mm out in various places, but a bit of persuasion with a 'G' clamp makes all the difference.
Note the temporary bracket attached to the dash board mounting anchor nuts, and the 'G' clamp to help line things up.
Once we were happy with the dimensions, I started to seam weld the pillars. Once that was done we concentrated on finishing the windscreen pillars so that the windscreen could go back in. It is worth taking a bit of time over this as (hopefully) it ain't gonna be done again. I reinforced the front skin from the A-pillar to the plenum chamber on the inside with a small plate with holes drilled to allow a plug weld above and below the join, this is done because the A-pillar is made up of three pieces, the centre piece is not accessible from the outside. I also made up two 2mm reinforcement plates for each side which are fitted over the join on the A-pillars at the bottom, this is between the upper and lower dashboard mounting holes but on the inside and outside of the pillar, this was because the front of the A-pillar is difficult to weld. The only thing you can do is make sure that the two edges are nice and clean prior to the tacking on phase and then weld them as best you can. The reinforcements give extra support. I spent the evenings of the next week making up plates to fit to the inside of the seam and tacking them on, ensuring the alignment of the lower original skin and the new upper skin. Basically, I kept on making up plates and patches until I was happy that the integrity of the front structure was restored. Once all were in place, it was just a case of doing a seam weld right across the front (in short sections to prevent distortion). In places there was quite a large gap between the upper and lower skins so a seam weld was made to both sides of the reinforcement plate that had previously been tacked to the inside. The reinforcement plates weren't absolutely necessary but if you feel they are needed, they won't hurt. The area where the seam runs across the upper part of the air intake was easy as there are three skins here, the inner plenum chamber, the intake box and the outer skin. This was just seam welded on the inside and then the outside.
Once I was happy, then I started grinding (I did not bother with the inside as it is not going to be seen, though I did use 'Grey Stripe' seam sealer along the join). The most difficult bit of grinding being the upper channel that the intake grille sits in, I used a new grinding disc as it had a nice square edge and carefully ran backwards and forwards until the weld was nice and flat, the two ends where there is a curve in the channel were grinded into the skin either side and then repaired with a patch, (what I actually did was to not make much effort in this area in the initail weld sequence and finished it properly when the channel was finished. The off-side door needed a couple of packing pieces behind the hinges due to the door aperture being 2mm wider than it was before we started. The new piece was from a '73 bus, and ours is a '72 hence the gap where the late indicators went. The profiles are the same, and by the time a full set of reinforcing plates have been put in at the back, it is easy to fill. You need to pull the interior light wiring back down the pillar, which proved to be a real pain, as it kept on catching on the new welds inside the pillar. Don't forget to use a new windscreen seal!
In case you are wondering, "join at the top" means put the windscreen seal in with the join (in the seal) at the top of the screen.
All in all it was a lot of hard work, the worst bit was grinding a bit off, offering it up, measuring, removing, grind a bit more off......... We started at about 9.00am on a Saturday, we had the new piece welded in on Saturday night. On Sunday morning I cleaned up and filled the weld on the A-pillars at the top cut point, sprayed it and we fitted the windscreen (with nice new seal) at about 4.00 pm Sunday. The rest of the week I spent about 3 hours per night welding in the reinforcements and filling everything in and getting a good exterior finish. By 3.00 pm the following Monday all was finished and from the outside it is impossible to tell what happened. The inside shows some evidence, primarily in the reinforcement plates on the A-pillar around the dashboard anchor nuts and of course the great run of weld above the plenum chamber though when it was covered in seam sealer and painted, the dashboard etc re-fitted it is virtually invisible.
Not impossible but a bit awkward and fiddly.
I borrowed (well nicked) this next paragraph from Andy but he is absolutely right so take note!!