BRAKE MASTER CYLINDER, fits 1973-1979 Buses equipped with brake servo. Made by JP Group 85mm hole spacing for reservoir. (1967 and earlier buses use 211611301E) *PLEASE NOTE: This master cylinder will fit 1971-1972 buses with a brake servo if you replace the reservoir with a 1973-1979 version.**PLEASE ALSO NOTE: A power bleeder must be used when installing this master cylinder. This is necessary to fully evacuate air from the unit.