BRAKING AND HYDRAULIC FAN SYSTEM
1. The brake and the hydraulic fan system pump is a variable displacement axial piston pump. When the engine
is operating, the pump will produce flow in order to satisfy the demands of the brake system and hydraulic fan
systems. The pump control valve is mounted on the piston pump. The pump control valve has two functions.
The pump control valve controls system pressure and it is load sensing; therefore, it will only produce enough
oil flow in order to satisfy the demand of the brakes and the hydraulic fan system. The brake system has
priority over the hydraulic fan system.
Figure 28. Piston Pump and Pump Control Valve.