The left rear quarter is the area of the body that needs the most attention, as not only do I have the rusty wheel arch, sill and lower rear corner to deal with, bit it’s also somewhat dented too. Some of the dents were straightened by hand whist doing the rust repairs but a lot of careful prep is going to be needed to make this part of the car look good under black paint. Before I could think about that though, I had the rust to deal with. The left rear wheel arch only looked a little bit worse than the right to begin with but actually turned out to need considerably more work. As on the right hand side, I had a new inner arch panel (part # 76713-K0130) and a rear quarter from a late 710 saloon (part # 78113-N7430) to help make the repairs, but even with these to help me a fair bit of fabrication was still needed.
First step was to remove the sill end closing panel inside the arch and chop out the inner arch section and asses how much of the outer arch needed replacing. The sill end closing panel was removed by grinding out the spot welds with a die grinder to try and keep the panel intact as it would be repaired and re-fitted later. It was clear right away that most of it was going to have to be replaced but little of the rust extended out beyond the first crease in the wheel arch flare. The rear end of the inner sill adjacent to the cross-member mount also needed repair so that was tackled first. The area is formed from two layers so the repair was done in the same way to recreate the original structure.
The saloon rear quarter could provide me with just over half of the rear arch repair I needed so it was cut up to provide both the arch and lower rear corner repair panel. A section was cut out of the old wheel arch where the new replacement panel would fit and the inner arch clamped into place to provide a guide for positioning the new section of arch.
Before the inner arch could be used it was trimmed to fit the same way as for the previous side. The new section of wheel arch was cut and flush welded to the original metal using the slow process of building up the weld a small bit at a time to reduce heat and distortion. A relatively high power setting was used to get good weld penetration as the outer weld was to be ground smooth. The penetration was enough for the weld to form a bead on the oposite side of the joint ensuring it will remain strong when ground back on the outside. The lower rear corner repair from the saloon isn’t quite the same shape as on a hardtop so care was needed to get the repair panel fitting correctly. On a coupe the body swage line curves up higher just before the rear bumper than on a saloon, a difference which is not noticeable without direct comparison.
Having got two thirds of the job done, all the remained was the forward half of the wheel arch and the area where the rear quarter panel attaches to the sill rearward of the door. All of this had to be fabricated but before replacing any of the outer metalwork, the sill closing panel needed to be refitted. As with the right hand side, I repaired the original panel rather than trying to fabricate a new one. This is a tricky panel to make from scratch so it’s easier to just repair the old one. The panel was acid dipped overnight to remove all the old rust before new pieces were made and welded in. The closing panel was then welded back on using plug welds though the old holes made whilst removing it and fresh holes punched around the new inner arch lip. The weld were ground smooth and rest of the arch and quarter panel was then reconstructed.
The finished repair will still need some finishing with body filler but getting the shapes and repairs as accurate and as smooth as possible in metal does at least mean only a very thin skim is needed. This is particularly important in the rear wheel arch area as the wheel arch shape is actually quite subtle and difficult to recreate with body filler.
Next on the agenda… replacing the rear valance.