Three different brake master cylinders were used on the MGC, and identifying which type is fitted is essential before ordering replacement or repair components. The single-circuit master cylinder is fitted to all UK home market and most export cars. It uses an integral filler cap with seal, and a single push rod connects to the brake pedal. A repair kit is available for this cylinder.
French and Benelux market cars use this same master cylinder but with a separate transparent plastic fluid reservoir connected by hose, rather than the integral cap. USA-market dual-circuit cars up to approximately 1968 use a tandem master cylinder with a remote drum-shaped transparent brake fluid reservoir, a different filler cap and seal, and its own push rod. From car number 3018 (approximately 1968 to 1969), USA and Canadian dual-circuit cars received a revised tandem master cylinder with a box-shaped reservoir sitting directly on top of the master cylinder body, a different cap and seal, and its own push rod with retaining circlip. Both dual-circuit types use their own specific repair kit.
Mounting
Single-circuit master cylinders are secured by one screw and one stud with washers and nut. Dual-circuit master cylinders are secured by two screws with spring washers. The mounting arrangements are not interchangeable between single and dual circuit types.