52-1 | “Hot” brush assembly with the retaining clip



The early outside plug 250 series engines used a small carbon brush assembly to activate the cooling fan clutch. This is a pencil-sized plastic assembly, held in place by a spring clip, with a small spring-loaded carbon brush that sends an electrical signal to activate a magnetic clutch to engage the radiator cooling fan. The design was improved on the later 250 cars with the addition of a second ground brush. The earlier assembly is shown on page 285 of Dick Merritt’s book Ferrari:Operating, Maintenance, and Service Handbooks 1948-1963. The later configuration, with the ground brush, is shown on page 170 of the “Carbooks” 275 Manual reprint. “Hot” Brush assembly with the retaining clip