The fourth day of welding and things start to get a bit more tricky here. Up until now I’ve had a decent number of replacement panels to use but I’ve got less to help me tackle the rear arch repairs other that one very useful part… a new outer section of the inner arch assembly (part # 76712-K0130). Having this piece at least helps me to reconstruct the outer arch to the right radius as well as providing the lower rear closing section at the rear of the arch. That part would be pretty hard to fabricate, much like the sill end closing panel (which I’ll tackle on Day 5). Amazingly this inner arch section is the same on both the hardtop and the four door saloon. It would have been nice to have new rear quarters for the hardtop but they seem to be totally unobtainable, however I did have some saloon rear quarters out of which I cut the lower rear corner and some of the arch lip.
I had already removed the sill end closing panel (pictured above right) when I removed the sill and unfortunately it was in a bad way. This panel will have to be carefully reconstructed so it can be refitted later. The inner arch panel extends forward inside the rear quarter to meet the sill. Unlike the sill, it’s all but impossible to remove the inner arch and replace it in it’s entirety unless you are removing the outer rear quarter as well. As I don’t have new rear quarters this is out of the question so it’s necessary to trim the new panel down to fit. inside the sill end area, I cut away the rusted parts of the metal and trimmed away the metal on the new panel to match.
Next the old inner arch had to be removed. This was accomplished by drilling out the spot welds around the arch lip and then by cutting about 8mm outboard of the seam where the two halves of the inner arch assembly meet with a 1mm cutting disc on an angle grinder. It’s not possible to fit the inner arch with it’s outer lip intact so I left that part in place and overlapped the new panel welding it near to the seam. Once the welds here are ground smooth and the seam sealer replaced the join won’t be visible.
Once the inner arch repair was welded in, I could start making repairs to the outer arch. In most places only the very edge of the arch lip had rusted in the seam so I could just fabricate thin strips of metal with holes punched along the length for plug welding. Down near the front edge of the arch it was a little more complicated and required some quite time consuming fabrication of repair pieces, all of which were flush welded in and the welds ground back smooth.
The final result looks quite neat and the nice thing is, by fitting a new inner arch, I now know for certain that there’s no rust in the rear arch now. The same will be done shortly on the other rear arch. Once these areas are rust treated with cavity wax I shouldn’t see any rust for a very long time! Next stage will be to replace the lower rear section of the rear quarter rearward of the arch and the repair the sill end closing panel.