PARTS WASHER 4C3874 - Caterpillar

Illustration 1 g03556137The brake accumulators are located in the compartment behind the ladder on the right-hand side of the cab. The compartment door is removed for clarity.The accumulators for both the front and the rear service brakes are located behind the ladder on the right side of the machine. The accumulators are mounted in a vertical position. The accumulator for the rear service brakes and park brake is positioned to the inside of the accumulator for the front service brakes.
Illustration 2 g00291611
(1) Nitrogen charging valve. (2) Chamber for the nitrogen gas. (3) Piston. (4) Pressure oil chamber. (5) Accumulator. (6) Outlet to service brake control valve.
The two accumulators for the service brakes have piston (3), which is sealed. The piston moves back and forth inside the bore of each accumulator. The chamber for nitrogen gas (2) contains a charge of approximately 5500 kPa (800 psi) of dry nitrogen gas. The dry nitrogen gas is put into the accumulator through nitrogen charging valve (1).Oil from the accumulator charging valve flows through outlet (6). The oil then enters pressure oil chamber (4). The oil then pushes piston (3). The movement of the piston causes the dry nitrogen gas to compress. When the pressure in the accumulator reaches the cutout pressure, the supply of oil is stopped by the accumulator charging valve.When a brake pedal is pushed, oil from chamber (4) flows outward through outlet (6). This oil flows to the service brake control valve and the oil then applies the service brakes.