The MGB GT V8 brake system uses 10.75 inch front discs with single-piston floating calipers, 10 inch by 1.75 inch rear drums with leading-trailing shoes, a single-circuit hydraulic system, and a servo as standard fitment from the start of V8 production. The pedal-operated master cylinder is mounted on the bulkhead at the brake pedal, with the remote-mounted Lockheed servo on a bracket on the opposite side of the engine bay (the non-direct-acting type fitted on UK MGBs throughout the V8 production period). Brake lines run along the chassis to the front calipers via flexible hoses at each front wheel, and to a T-piece at the rear axle which feeds short flexible hoses to each rear wheel cylinder.
Front Disc Brakes
10.75 inch solid discs at the front provide the primary braking force, with single-piston floating calipers giving even pad wear and good braking efficiency. Pads, discs and calipers are V8-specific items in their dimensional specifications, dictated by the V8's higher kerb weight and braking requirements compared with the four-cylinder MGB.
Rear Drum Brakes
10 inch by 1.75 inch rear drums with leading-trailing shoe arrangement provide rear braking. The rear drums are shared with the contemporary MGB four-cylinder specification, the V8's braking emphasis is on the front discs, with the rear drums providing the secondary braking effort and the handbrake function.
Servo and Master Cylinder
The brake servo (vacuum-assist Lockheed type) was fitted to the V8 as standard from the start of production, a Lockheed non-direct-acting unit (GSM125) mounted on a bracket on the opposite side of the engine bay to the bulkhead-mounted master cylinder, with brake fluid pipework connecting the master cylinder to the servo and onward to the brakes. The master cylinder is a single-circuit type. The single-circuit braking specification was the standard for UK V8s throughout production, dual-circuit brakes did not arrive until the 1977 model year, after V8 production had ended.
Sub-Sections
Front Brakes, Rear Brakes, Handbrake, Brake Servo, Master Cylinder, Brake Lines and Pedal Box Assembly each cover their respective subsystems. Upgrades and Alternatives covers braided brake hoses, copper brake pipe kits, servo kits, uprated discs and pads, and brake lubricants and tools.
MGOC Spares
MGOC Spares supplies the full range of MGB GT V8 brake components, see individual sub-sections for details.