This section covers the operating hardware for the MGA bonnet, the hinges at the rear that allow the bonnet to pivot open, the lock mechanism at the front that secures it closed, the release cable linking the facia pull to the catch, the prop rod that holds the bonnet up during engine access, the rubber buffers that prevent metal-to-metal contact when the bonnet is closed, and the complete range of UNF fasteners for bonnet assembly and adjustment. Unlike the bonnet panel itself (aluminium-skinned, covered under the Front Outer Panels & Bonnet section), most of these operating items are steel pressings and fabrications and are therefore relatively straightforward to service, replace or adjust without the specialist aluminium-working skills needed for the panel.
Bonnet hinges, pair
MGA bonnet hinges are supplied as a pair, left and right are handed but matched as a set. The hinges mount at the rear of the bonnet to the scuttle/body junction, allowing the bonnet to pivot open toward the front of the car on its prop. Worn or stiff hinges cause uneven bonnet closing and premature wear of the bonnet skin at the hinge attachment points; replacement restores correct pivoting action and panel alignment.
Bonnet lock and sliding latch striker guide
The bonnet is secured closed by a lock-and-striker system: a striker pin on the bonnet engages with a sliding latch mechanism on the body, held by a spring-loaded catch. Complete mechanism components are stocked: the striker pin (fitted to the bonnet), the sliding guide (stainless steel improved version or standard mild steel), the bonnet lock spacer (setting the correct distance between latch and striker for consistent engagement), and the bonnet spring (holding the latch closed against the striker pin under vibration). The stainless-steel improved version of the sliding latch guide resists the corrosion that affects the original mild-steel guide over years of water ingress, and lasts significantly longer in service.
The standard version is also stocked for strict factory-original specification. On 1600 cars, the bonnet lock and safety catch are correctly painted body colour rather than black or natural steel, a point to note during concours restoration.
Prop rod and clip
The MGA bonnet prop rod holds the bonnet in the raised position for engine access. It stows against the inner side of the bonnet when not in use, held by a clip on the bonnet underside. When raised, the prop pivots out and locates in a socket on the body to support the weight of the bonnet. The bonnet prop clip is the stowage clip on the bonnet underside.
Both prop rod and clip are factory-specified black on all MGA variants (on 1600 cars the prop appears "on the wrong side" visually but is correctly black). A split pin and 5/16" plain washer are used to secure the prop rod at its pivot point.
Bonnet buffers, car set of 10
The bonnet buffer set (car set of 10) provides the rubber buffers fitted between the bonnet and the body shroud, preventing metal-to-metal contact when the bonnet is closed and absorbing vibration while the car is running. Worn or missing buffers allow the bonnet to rattle against the shroud and can damage the bonnet edge over time. The car set gives the complete factory-specified 10-buffer coverage in one item.
UNF fastener sizes
Complete UNF hardware is supplied in the sizes required for bonnet assembly. 10-32 UNF includes No. 10 screws (1/2" length), plain large washers, locking spring washers, and plain zinc nuts (32 TPI), for smaller bonnet-hardware fixings. 5/16 UNF plain washers are used at prop rod and similar pivot points. 1/4 UNF hex-head screws (5/8" and 1" lengths), plain washers, locking spring washers, and plain zinc nuts are used for bonnet-hardware fixings at the larger size range. 3/8 UNF thin locknuts are stocked where a locking function is needed on a 3/8 UNF fastener. No. 5 UNF recessed pan-head screws (32 TPI, 1/2" length) and plain zinc nuts cover smaller assembly items, with No. 5 × 3/8" self-tapping screws for sheet-metal attachments within the bonnet assembly.
Ordering considerations
For general service restoration of the bonnet operating hardware, the sliding latch guide, striker pin, spring, spacer and buffer set cover the critical wear items. The stainless-steel improved version of the sliding latch guide is the recommended choice for any car being restored for regular use, as the original mild-steel version is prone to corrosion and eventual failure. For concours restoration to strict factory-original specification, the standard guide is the correct choice.