The MGB clutch is hydraulically actuated throughout production. The clutch master cylinder is mounted on the pedal box alongside the brake master cylinder, with its own integral fluid reservoir. A Lockheed clutch slave cylinder is mounted on the right-hand side of the clutch housing and is operated by fluid pressure from the master cylinder via a copper pipe and flexible rubber hose.
Clutch Master Cylinder
The clutch master cylinder changed during the production run. The original type, identifiable by the absence of identification rings around the cylinder barrel, was used on early three-synchromesh cars. A revised master cylinder was introduced from the start of the Mark II model in late 1967 for four-synchromesh cars, with the mounting flange turned to allow the reservoir to lean away from the brake master cylinder. This was necessary to clear the larger brake fluid reservoir fitted to North American cars with dual-circuit brakes, though the change applied to all markets.
The master cylinder was revised again during the GHN5/GHD5 series, probably around 1973, and this later type can be identified by two concentric rings around the cylinder barrel. The later type is interchangeable with the previous type and is now recommended for fitting to all cars with the all-synchro gearbox in place of the original type. Two master cylinder versions are available: reproduction and quality replacement, both covering cars from 1968 onwards. Seal kits are available for both the earlier cup seal type and the later ring seal type, along with master cylinder filler caps in both original metal and later plastic forms, the piston return spring, and pushrod.
Clutch Pipe & Hose
The clutch pipe runs from the master cylinder to the flexible hose. Copper clutch pipes are available for RHD cars, with separate LHD pipes for early cars up to September 1976 and late cars from September 1976 onwards. The flexible clutch hose connects the rigid copper pipe to the slave cylinder. Both a stainless steel braided hose and standard rubber replacement hoses in reproduction and quality versions are available, covering all MGB, MGA, and Midget applications.
The banjo union connector and all associated sealing washers are available.
Slave Cylinder
The slave cylinder and its seal kit are both available in quality reproduction, along with the slave cylinder pushrod, clevis pin, and mounting bolts. A bleed screw and all associated pipe clips and hose locking nuts complete the hydraulic system hardware available.