From the outside it has always seemed that the problems with the van were just 'a bit of rust'. Once we started taking it to piece it became obvious that this was far from the full picture.
The bumpers on this T25 are resin-composite ones rather than the metal versions on earlier models. The rear bumper is made up of three sections, a long one across the back, and two end-cheeks. The rear section is bolted to a couple of long 'arms' which in turn push into the box sections forming the sides of the engine compartment.
The end cheeks bolt onto the ends of the rear bumper section and also bolt to the lower corner panels in two places.
The nearside rear bumper cheek had been drooping for a few years, so we expected that the bolt location holding it to the chassis would be corroded, and so we expected to need a new panel section for that, and also perhaps the wheel arch section too.
I believe this corner cheek got pushed into the side of the bodywork about seven years ago when someone borrowed the van and parked it at the top of a hill without putting the handbrake on properly and it rolled into a ditch, where it had to stay all night until they could get a farmer to come and pull it out.
We were right about needing both those panels
The big hole is where the bumper end-cheek bolts through the panel from the inside. The bumper comes right up to the swage line, and wraps round to the back of the wheel arch, so none of this corrosion is visible until you remove it.
Replacement panels are easy to obtain, and need a bit of 're-shaping' (hitting with a big hammer) to fit properly
A bit of work with a hammer in the wheel arch also revealed that the whole area around the back corner was corroded as well. There is a box structure in the back corner rearwards of the wheel arch, and the horizontal and vertical joint lines visible in this photograph are not just joins between two panels, they are actually joins where three surfaces meet to form the front and bottom of the rear box.
A large section of this was also corroded
This photograph is looking up through the floor of the van into what is effectively the left-hand side of the engine compartment. The metal panel at the top of the picture with the blue line drawn on it is the back of the wheel arch.
This corrosion is partly due to bad design. Above this section in the side of the van is a ventilator that allows heat from the engine compartment to escape. It also allows rain to get in and collect on the floor of that box, which is actually formed of two overlapping metal sections that are not welded but only sealed together with compound.
Combined with road salt and dirt on the outside of the floor this is a recipe for disaster.
In effect the entire lower rear corner of the van needed rebuilding. The blue line was part of the area which we drew to cut around, where the existing panels were sound enough to weld to.
Once that had been cut out it looked like this
The triangular section rising from the corroded floor forms part of a vertical box section rising all the way to the roof to strengthen the corner of the van and to help direct the air upwards to the ventilator in the side.
Some scraping that we did on the rear dropped lip showed that this seemed to be ok. All this is covered in factory-applied rubbery sealer, which appears to work well until water gets underneath it.
To repair this corner we had to make an 'L' shaped metal panel to fit inside the box, matching up to the flanges. This would seam-weld to the cleaned inside of the box, and the replacement rear bumper panel and wheel arch sections would plug-weld 'through' the partly-corroded flanges, trapping them in between.
A smaller 'L' shaped bracket was constructed to weld the bottom end of the vertical riser to the new floor of the box.
When all welded up it looks like new. Photos to follow.
The repaired panels.