FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
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Brake Master Cylinder: Description and Operation

Fig. 2 Master Cylinder Operation:




Operating the brake pedal moves pistons (1 and 4) forward. Fig. 2. Primary cups (2 and 5) slide over compensation bores (3 and 6), which creates balanced pressure in chambers A and B.
Chamber A acts on front right and rear left brakes. Chamber B serves left front and right rear brakes. If brake circuit fails, the brake pedal travel will increase considerably.
If second circuit fails, piston (1) will adjust the pressure building up in chamber A to push piston (4) in pressureless chamber B against tandem master cylinder housing and the first brake circuit resumes function. If the first brake circuit fails, piston (1) in pressureless chamber A will be pushed against spring-loaded cap (7) and the second brake circuit will have full action via chamber B.