The GMC227 stepped bore (.70"/.75") tandem brake master cylinder replaces most rectangular reservoir master cylinders used from Sept. 1978 until the combined servo-master was fitted in 1989. It is to be used on front-to-rear split braking systems only. Genuine AP/Caparo part, made in the U.K. It is a good idea to replace the CLZ0512 clevis pin and 31G0840 gasket during installation. Ref: GMC227, LM15121.
IMPORTANT FITTING INSTRUCTIONS: This unit must be bench bled before installation. Prior to installing the cylinder onto the vehicle, place a block of wood underneath the pedal to prevent the pedal from traveling all the way to the floor during final bleeding. If the pedal travels to the floor it will damage the internals of the cylinder and, if equipped, upset the PWDA switch. Using Silicone brake fluid will void any warranty.
If your Mini was manufactured prior to Nov 1985, you will need a brake pipe conversion kit, either BAU5654 for right-hand or BAU5655 for left-hand. Please follow the directions with the master cylinder exactly when fitting, since the connections to the pressure regulating valve are reversed compared to original.
The top outlet on the master cylinder is plumbed to the front brake circuit, the lower to the rear.