The inner sill provides strength to the chassis as part of the double box section that makes up the rocker assembly on an MGB. The driver’s side inner rocker was fairly solid except for the front 10 inches or so and right at the jack mount brace. Rather than cut out the entire rocker and destabilize the whole car we opted for some small repairs to the damaged sections.
Looking over the pinholes and pitting, we cut back to where the metal was within about 10% of full thickness. The We took a new inner sill repair panel and sectioned off the front for use in our repair.
After trimming and fitting the repair panel we welded it in place.
We cut out the area that rusted out beneath the brace which strengthens the jacking point, fashioned a repair piece with some of the leftover repair panel and welded it in place.