The final area to tackle on this side of the car is the front inner wing. Initial inspection only revealed rust in the most common area for these cars to go, the bottom of the strut tower just above the chassis leg, but once the underseal was scraped off from the inner wing, there were definitely a few more suspicious looking areas. The bottom couple of inches of the inner wing panel overlaps the chassis rail on 710s, so that whole area is double skinned. Any moisture coming down the inner wing in the engine bay runs straight into this seam, as it’s not sealed, so rust can build up in there, rotting the section from the inside out. Not wishing to take any chances of future rust developing, I figured it was time to chop the lot out and replace it.
The phot above left shows the suspect areas. The rusty hole in the center is obvious, as is the blistering near the steering box mount to the left of the picture, but the rust is less noticeable near the cross-member mountings. The area towards the front of the chassis had no visible rust at all but the metal had swollen out between the spot welds indicating the likely presence of rust inside. I cut the lower section of the inner wing away in three sections, peeling it away from the chassis rail behind. The true extent of that small patch of rust visible in the first picture, at the bottom of the strut tower, is fully revealed once the top layer is cut away (above right). The spot welds that attach the panels in this area are very large, so it wasn’t practical to use a spot weld drill. Instead I employed an air powered die grinder, with a ball shaped carbide burr, with which I ground each spot weld away.
Having cut the outer layer away, it’s clear how much rust was hiding inside the closed section. This would spell trouble in the future so best to get rid of it now and rust treat the area to prevent it happening again. Once everything was cut out, the first bit to be replaced was the bottom of the strut tower itself, which is a separate section overlapping the inner wing inside the engine compartment. The bottom couple of inches of this piece had rusted out, so a repair panel was fashioned and flush welded to the original. Later this repair will have to be tidied up within the engine compartment, but that will require removal of the steering box and all of the brake lines, so will be tackled when I repaint the engine compartment.
I replaced the metal I had removed from the inner wing in three sections, in the same manner as it was removed, using the old pieces had I cut out as templates. The sections required are fairly straightforward to make, with just one raised section to form into the repair panel over the brake hose mount. Holes were drilled to plug weld the new metal into place. Before attaching the new sections, the original metal underneath was coated with a thin layer of Bilt Hamber Dynax S50 to protect from future rust. The top of the seams will be sealed when the engine compartment is painted. Once all three sections were welded in, all the welds were ground back smooth.
With the inner wing area finished, that’s the entire right side of the car repaired and time to turn it round and get the left side started!