A sound seat frame is the foundation of a good seat retrim, fitting new foam and covers to a bent or corroded frame produces a seat that will never sit correctly regardless of the quality of the materials fitted above it. The MGB seat frame changed fundamentally during the production run, and the correct frame must be in place before foam, covers, and hardware are ordered.
The original 1962 to 1968 seat used a non-reclining frame with a tubular steel structure, painted black. The seat squab folded forward but could be locked upright by a bolted-on bracket at the bottom rear. The squab rake could be adjusted by two bolts at the bottom of the squab, but there was no reclining mechanism, the seat back angle was set by the position of these bolts and remained fixed during use. The cushion was built up with a foam rubber pad over a rubber diaphragm base from April 1963, earlier cars using Pirelli webbing straps.
Reclining Frames (1969 Onwards)
For the 1969 model year, the seat frames were modified and adjustable reclining seat backs were introduced for the first time. The reclining mechanism was activated by a chrome-plated handle on the inside edge of the seat squab, with a proper seat lock-down mechanism featuring a black knob release handle on the outside edge. This was a substantial change to the frame structure, the reclining mechanism is integral to the frame, and a non-reclining frame cannot be converted to reclining by simply adding the mechanism. The 1969 recliner frame was itself revised for the 1970 model year, and this later reclining frame continued to the end of production in 1980, though the foam profile, seat cover pattern, and headrest type changed several times across this period, the fundamental frame structure remained the same from 1970 onwards.
On a car that has been in service for decades, the seat frame can corrode, particularly around the lower edges where moisture from wet carpets or a leaking hood wicks into the metalwork. On Roadsters this is exacerbated by the exposure to weather that the cabin inevitably receives. A distorted frame will cause the seat to sit at an angle, lean to one side, or fail to engage the runners correctly.
Where a full restoration is planned, inspecting and if necessary replacing the frame before ordering foam and covers avoids having to strip the completed seat later.
Replacement Frames
Replacement seat frames are available for both right-hand and left-hand seats across the production range. The seat diaphragm, the rubber suspension base used from April 1963 to 1972, or the seat webbing that replaced it from approximately 1972 should be inspected and renewed at the same time. The two can be interchanged, but some re-drilling of attachment holes in the seat frame may be necessary. A calico webbing cover is available to protect the foam base from abrasion against the webbing or diaphragm beneath.