The sill and floor structure is the area most vulnerable to corrosion and the one with the most direct bearing on the structural integrity of the body. The monocoque construction relies on the double-section sill box running the full length of the car between front and rear wheelarches for primary longitudinal strength, so a corroded or poorly repaired sill leaves the body without the rigidity it was designed with and affects the way doors fit and close. The sills are linked transversely by the two main floor panels and the transmission tunnel.
Sill Kits & Components
Sill kits are available in three-piece and six-piece configurations for both left and right hand sides, the six-piece kit providing the most comprehensive replacement and the recommended choice for a full sill restoration. Outer sills and inner sills are available in Heritage and reproduction specifications. The sill end filler, the closing panel bridging the outer and inner sill at the rear, is available separately, and the inner step sill, which forms the bottom structural member running inside the outer sill, is available as a full-length Heritage pressing or as a four-foot repair section for the most commonly corroded area.
Floors, Castle Rails & Jacking Points
Castle rails form the bottom longitudinal member beneath the floor pan and sill structure, the lowest point of the body and the most exposed to road contamination. Floor pans are available for 3-synchro and 4-synchro cars as separate specifications, reflecting the different transmission tunnel profile, and A-post assemblies are available for pre-1975 and post-1975 cars. On the MGC, front floor repair panels are model-specific, reflecting the modified floor pan that was necessary to accommodate the torsion bar front suspension and the different engine and gearbox mounting geometry, so MGB front floor panels cannot be used, although rear floor sections and the transmission tunnel are broadly shared. Jacking point bracket assemblies and reinforcement plates are available individually, the jacking points being a common corrosion site that should be replaced as part of any sill restoration to ensure the car can be safely raised.
Rear Floor, Boot & Tunnel
Floor corrosion typically affects the leading edge of the front floors where water enters past the door weatherstrips, the rear floor junction with the rear wheelarch, and the spare wheel well, with this double-sided attack from road spray below and moisture trapped beneath carpets above usually hidden under apparently sound carpet. The boot floor area covers the rear of the bodyshell with a recessed spare wheel well, where water entering past a tired tailgate seal collects in the lowest part of the boot floor, making this a particularly common corrosion site. The transmission tunnel runs along the centre of the cabin floor providing clearance for the gearbox, propshaft, and exhaust, and is rarely affected by corrosion in normal use, with tunnel work more commonly required for fitment of larger gearboxes than for repair. Spare wheel wells, boot floor panels, rear wheelarch inner panels, and floor repair sections are all available individually.