The MGA bonnet is an aluminium-skinned panel over a steel X-brace reinforcing frame, with a wood stiffening batten and anti-drumming felt on the underside. It is hinged at the rear, opening forward to give access to the engine bay, and is released from inside the car by an internal pull under the left-hand side of the facia. A prop stay supports the bonnet when raised, and a bonnet lock and safety catch at the front secure the bonnet when closed. The aluminium construction is a significant factor in MGA bodywork because the bonnet requires different repair techniques from the steel panels elsewhere on the body, aluminium cannot be welded with standard MIG equipment, and panel-beating aluminium requires softer hammers and different dolly techniques.
Pushrod MGAs carry a factory black horsehair pad on the bonnet underside at the front; on Twin Cam cars the bonnet has increased curvature at the front compared with pushrod cars, an identification detail when establishing factory originality. The Bonnet & Fixings section is divided into two sub-categories covering the bonnet panel and its release and mounting hardware.
Front Outer Panels & Bonnet
The Front Outer Panels & Bonnet sub-category covers the complete bonnet assembly alongside the front wings and other front outer body panels. This is cross-linked from the main Bodywork > Panels > Front Outer Panels & Bonnet section, and includes the bonnet skin, X-brace frame and associated wing panels. Full detail is covered under that node.
Bonnet Fixings & Release Cables
The Bonnet Fixings & Release Cables sub-category covers the bonnet's operating hardware, the release cable from the facia pull to the bonnet catch, the bonnet catch mechanism itself, the safety catch, the prop stay, hinges, and associated fixing hardware. These are the components required for bonnet operation and restoration, separate from the bonnet panel itself. Full detail under the Bonnet Fixings & Release Cables node.
Bonnet paint and finish details
Several bonnet-area components should be finished in specific factory colours during restoration. On 1600 cars, the bonnet prop is correctly black (even though it appears to be on the "wrong" side visually), and the bonnet lock and safety catch are correctly painted body colour rather than black or natural steel. Twin Cam bonnets have the increased front curvature; pushrod bonnets including all 1500, 1600, 1600 Mk II and De Luxe cars share the same bonnet profile across the range.
Aluminium panel care
The MGA bonnet's aluminium skin is vulnerable to electrolytic corrosion where it meets the steel X-brace frame at fastener points, and to fatigue cracking at high-stress areas if the bonnet has been flexed repeatedly. Cars being restored should have the bonnet skin carefully inspected before deciding whether to re-skin the existing X-brace frame (if the frame is sound but the skin has damaged areas) or replace the complete bonnet assembly. For fatigue-cracked bonnets, specialist aluminium welded repair by a panel-beater experienced with 1950s aluminium coachwork is required.
Ordering considerations
For restorations, start with the bonnet panel and X-brace frame condition assessment before ordering bonnet components, a good-condition frame can be re-skinned at significantly less cost than a complete new bonnet assembly. For operational restoration (replacing a broken release cable, worn bonnet catch, or damaged safety catch), the Bonnet Fixings & Release Cables sub-category has the specific items. Confirm the car's variant before ordering any variant-specific components, Twin Cam bonnets are not interchangeable with pushrod bonnets due to the different front curvature.