The bonnet is hinged at the rear and opens forwards, secured at the front by a bonnet catch. On the MGB it was originally manufactured in aluminium from the start of production in 1962, changing to steel during 1969 at approximately the same time as other changes were made to reduce the aluminium content in the car, a decision driven by cost rather than engineering. The two are visually identical from the outside but differ in weight and in how they respond to dents and corrosion, the aluminium bonnet being lighter but more vulnerable to distortion, while the steel bonnet is heavier but can be conventionally repaired and filled. The MGB GT V8 uses the steel bonnet shared with the contemporary four-cylinder MGB GT, and notably the V8 fits within the standard engine bay without a bonnet bulge or modification, a key piece of MG engineering that makes the V8 visually similar to the four-cylinder car at first glance.
Hinges & Stay
Bonnet hinges at each side of the rear bonnet edge allow the bonnet to pivot upward for engine access, and incorporate spring loading to assist with raising the bonnet and holding it open. Worn hinges allow the bonnet to sag at the rear, causing visible misalignment with the surrounding body, so hinge renewal restores correct shut lines and bonnet movement.
The original bonnet prop rod was replaced by a rubber-bushed bonnet stop in May 1963. A telescopic strut replaced the original-style prop on LHD cars from 1976, repositioned on the right-hand side to avoid fouling the brake servo. Gas-filled telescopic struts are available as an upgrade on all cars, holding the bonnet open without fumbling with a prop rod and allowing the bonnet to be closed single-handed.
Bonnet Catch & Release Cable
The bonnet catch at the front holds the bonnet closed under spring tension, and pulling the bonnet release inside the cabin operates a cable that releases the catch, allowing the bonnet to spring up to the safety catch position. From the safety catch, the bonnet is opened by reaching under the front edge and disengaging the catch by hand. The release cable runs from a pull under the facia to the locking platform at the front of the car.
The original release pull was a large knob marked 'B', changed later to a T-shape with a bonnet-open symbol at approximately the start of rubber bumper production. A stiff or seized release cable is a common issue on older cars, and a new cable restores smooth operation. Cable, catch mechanism, and safety catch are all wear items renewed during major restoration work.
Bonnet Seal & Hardware
The bonnet seal sits between the bonnet and the front shroud panel, preventing water ingress into the engine bay and reducing wind noise. Bonnet hinges, hinge bolts, bonnet buffers, and the complete range of bonnet mounting hardware are available alongside the main bonnet components. Particular attention should be paid to whether the car is chrome bumper or rubber bumper when ordering shroud assemblies, as the front shroud assembly differs between the two specifications.