The Classic Mini braking system evolved across production, and the first step before ordering any brake component is identifying whether your car has front drum brakes or front disc brakes. All Classic Minis use rear drum brakes throughout production, the distinction is at the front only.
Earlier standard models used drum brakes on all four corners, while later models and all Cooper variants were fitted with front disc brakes. The two front brake systems require completely different components, drums, shoes and wheel cylinders for drum-braked cars; discs, pads and calipers for disc-braked cars, and nothing is interchangeable between them. The front hub, wheel bearings and driveshaft assembly also differ between drum and disc brake configurations.
Front Drum Brakes
The front drum brake assembly uses a leading shoe arrangement within a brake drum mounted on the front hub. Each side has a backplate with adjusters carrying two wheel cylinders (four per axle), a set of brake shoes, return springs and locating springs. The wheel cylinders are handed, right-hand and left-hand brake sides use specific cylinders that are not interchangeable.
Front Disc Brakes
The front disc brake assembly uses a solid disc secured to the hub by bolts, with a two-piston caliper. Calipers are handed, right-hand and left-hand, and must be fitted to the correct side. Dust covers are fitted to protect the disc and caliper assembly from road debris and are also handed, with a separate support bracket for each side. Caliper rebuild kits, individual pistons, bridge seals between caliper halves, bleed screws and brake pad fitting kits (including retaining springs and split pins) are all available individually.
Rear Drum Brakes
All Classic Minis use rear drum brakes throughout production, but the rear drums differ between wheel sizes. Cars with 10-inch wheels (848cc, 998cc and 1098cc models up to 1984) use one drum specification, while cars with 12-inch or 13-inch wheels (1275 GT, Mini 25 and all models from 1984 onwards) use a drum with a ¾-inch integral spacer. The two drum types are not interchangeable. Complete rear backplate assemblies are available from the original manufacturer, including backplate, shoes, springs, adjuster, ¾-inch wheel cylinder and handbrake lever, everything apart from the drum itself to renew the entire rear brake in one operation.
These assemblies fit the vast majority of Mini saloons from 1976 onwards. The exceptions are some 1976 to 1977 1275 GTs and some other saloons from 1976 to 1980 with diagonally split brake systems, which used different diameter wheel cylinders.
Rear Wheel Cylinder Sizes
Three rear wheel cylinder bore sizes were used across production, and the correct size is determined by the brake circuit type and model. The ¾-inch diameter cylinder is used on most models with front/rear split dual circuit brakes. The 9/16-inch diameter cylinder is used on models with diagonally split dual circuit brakes from 1976 to 1980, except the 1275 GT. The ½-inch diameter cylinder is specific to the 1275 GT with diagonally split dual circuit brakes from 1976 to 1977.
Bare replacement backplates are supplied to the latest specification and require the wheel cylinder locating pin holes to be redrilled for the small number of early cars that used the non-standard cylinder diameters.
Brake Adjustment
Rear brakes on the Classic Mini are manually adjusted and do not self-adjust. The adjuster mechanism uses a wedge and tappet arrangement that pushes the brake shoes closer to the drum as the adjuster is turned. Regular adjustment is essential, shoes that have not been correctly set leave the majority of braking effort to the front, producing unbalanced, front-heavy stopping. Drum condition should always be inspected before fitting new shoes, shoes worn down to the rivets will score the drum surface, and a scored drum cannot be corrected by new shoes alone.
MGOC Spares Range
This category in the MGOC Spares Classic Mini range covers front and rear brake drums for all wheel sizes, front brake discs and securing bolts, dust covers and support brackets, front calipers (new outright and exchange reconditioned), caliper rebuild kits, individual caliper pistons and bridge seals, brake pads with fitting kits, brake shoes with return spring sets, adjuster kits with wedges and tappets, front and rear wheel cylinders in all bore sizes, wheel cylinder repair kits, complete rear backplate assemblies and bare backplates, bleed screws, and all associated hardware and fixings.