Brake proportioning valve as used on all Mk1 and Mk2 classic Minis, and all classic Mini Cooper and S models through Mk3. Mounts at the front of the rear subframe. This valve is identical to 21A2031, except a stronger internal spring 27H6620 is fitted to the 21A1774 valve. Ref: 21A1774.
See 21A2031 for Mk3 cars (not including Cooper S) to 1978, except Canadian market cars, which use 13H7757 inertia valve.