Three different braking systems were fitted to MGAs across the model's production run, which makes brake parts selection one of the most variant-critical areas of the car. The 1500 uses Lockheed drum brakes at all four wheels. The Twin Cam and De Luxe use 11-inch Dunlop disc brakes at all four wheels. The 1600 and 1600 Mk II use Lockheed front discs with rear drums.
The three systems share almost no common parts, and the front hubs, stub axles and steering knuckles also differ between them. This section covers MGA brake parts across seven sub-categories: front brakes, rear brakes, handbrake, brake lines, master cylinder and pedal box, brake fluid, and brake-related upgrades.
MGA 1500, Lockheed all-drum brakes
The 1500 runs Lockheed drum brakes on all four wheels. Drums are 10 inches in diameter and 1¾ inches wide at both ends, painted black. The front brakes use two wheel cylinders per drum giving two leading shoes; the rear uses a single wheel cylinder with one leading and one trailing shoe.
Original lining specification is Ferodo DM13, size 9.6 x 1.75 inches, giving 67.2 square inches total lining area at both front and rear. A combined brake and clutch master cylinder with integral supply tank sits on the horizontal shelf behind the engine, with pendant pedals directly below passing through a one-piece black rubber fume excluder. Pedal design was modified at car/chassis 58713. Rear brake pipe connections were standardised to UNF threads at car/chassis 27989 (disc-wheeled cars) and 28540 (wire-wheeled cars); the banjo connection to the rear wheel cylinders was changed from a straight to a right-angle type at car/chassis 22741.
Twin Cam and De Luxe, Dunlop all-disc brakes
The Twin Cam and De Luxe use 11-inch Dunlop disc brakes at all four wheels, the only MGA variants with four-wheel disc brakes. These cars have separate brake and clutch master cylinders, with different brake pipe runs from the pushrod cars. The disc brake calipers were modified at approximately car/chassis 836. At car/chassis 997, the master cylinder box was modified to avoid fitting a taper packing between master cylinder and box.
The De Luxe uses a slightly modified Twin Cam master cylinder, and a factory service kit was made available to convert an original Twin Cam master cylinder to the later specification. Factory-recommended fluid is Wakefield Crimson (later Dunlop disc brake fluid), or any brake fluid to specification SAE70.R1 or SAE70.R3. The handbrake operates on special pad carriers attached to the rear disc calipers, an arrangement described in the Identification Guide as "not terribly effective and troublesome to set up".
1600 and 1600 Mk II, Lockheed front disc, rear drum
The 1600 and 1600 Mk II (other than De Luxe, which inherit the Twin Cam architecture) use 11-inch Lockheed front discs with 10-inch rear drums. Front disc studs were replaced by bolts at car/chassis 69505 (disc-wheeled) and 70276 (wire-wheeled). Improved brake pads were introduced at car/chassis 78106 and recommended for all earlier cars. On the 1600 Mk II, brake disc dust covers were added from car/chassis 102589.
Rear drums match the 1500 dimensions but use later DON24 linings, size 9.63 x 1.7 inches. From the start of 1600 production, the brake pedal arm was redesigned and the master cylinder received a deeper supply tank cover. The pipe runs and handbrake mechanism are largely carried over from the 1500.
Handbrake, common to all variants
The handbrake is a fly-off type fitted on the right-hand side of the propeller shaft tunnel, sitting horizontally in the off position. It activates the rear brakes by cable. The lever is chrome-plated with a plain black handgrip, and the setting button is also chrome-plated. The lever and cable arrangement is common across all MGAs; what differs is the rear actuation, drum-shoe expanders on pushrod cars, special pad carriers on the rear disc calipers on Twin Cam and De Luxe.
Ordering considerations
Brake parts ordering starts with the variant, pushrod 1500, pushrod 1600 / 1600 Mk II, Twin Cam or De Luxe. Within each system, the chassis number determines production-change specification: on the 1500 (22741, 27989, 28540, 58713); on the Twin Cam (836, 997); on the 1600 / 1600 Mk II (69505, 70276, 78106, 102589). Wheel type (disc or wire) affects front hub and stub axle specification, covered under Stub Axles & Hubs within Suspension & Steering.