WASHER 2N4641 - Caterpillar

Illustration 1 g03668046
View of the location of the control manifold (brake)
Illustration 2 g03734017
(1) Port for the low front brake pressure switch
(2) Check valve
(3) Auto apply pressure switch port
(4) Plug
(5) Check valve
(6) Port to brake supply accumulator pressure gauge
(7) Port to dry park brake pressure gauge
(8) Port for the dry park brake pressure switch
(9) Port for the low rear brake pressure switch
(10) Port to park brake supply
(11) Brake valve port
(12) Pilot valve return port
(13) Park brake solenoid valve
(14) Brake accumulator drain solenoid
(15) Load brake solenoid
(16) Port to the load brake shuttle
(17) Port to the service brake
(18) Check valve
(19) Port to the brake control valve "P2"
(20) Port from the front brake accumulator
(21) Port from the rear brake accumulator
(22) Brake valve return port
(23) Pressure reducing valve
(24) Brake accumulator drain port
(25) Port from the supply brake accumulator
(26) Supply port
(27) Brake accumulator drain solenoid
(28) Port to the brake control valve "P1" The brake manifold assembly is a rectangular shaped metal valve with several external poppets and multiple hose connections ports. The brake manifold assembly is mounted inside the hydraulic components box. The brake manifold serves as a centralized assembly to provide the following provisions:
Park brake solenoid valve - dual coil, latching type, electric solenoid valve that controls the flow of pressurized oil to the park brake system to allow the brakes to be applied or released.
Park brake shut-off valve - electric solenoid/check valve assembly that prevents the flow of oil to the system except when the solenoid is energized. The system is wired to allow this only to occur when the operator is holding the Park Brake Switch in the Release position.
Load brake solenoid - electric solenoid valve cartridge that control the flow of pressurized oil to the load brake system to allow the rear brake service calipers to be applied or released.
Accumulator manual drain- cartridge assembly with either a manual pull type valve assembly (spring loaded to the closed position) or a needle type valve that provides a means of manually releasing any pressure remaining in the brake accumulator.
Accumulator automatic/manual drain- on early production manifolds and trucks, there was an electric solenoid valve cartridge assembly that controlled the flow of oil from the rear brake accumulator system to the tank caused the rear (and thus the supply) accumulators to drain each time the truck's Master Switch was turned Off. An externally controlled manual drain provision was incorporated into this cartridge.
Low brake pressure switch - electric switch assembly that monitors the system supply pressure (accumulator pressure) and causes a cab dash Low Brake Pressure indicator to light.
Park brake pressure switch - electric switch assembly that monitors the park brake system pressure and causes a cab dash Park Brake indicator to light if the pressure decreases to a level at which the park brake calipers will apply.
Auto apply pressure switch – available electric switch assembly that monitors the brake system supply pressure and causes a cab dash auto apply solenoid to shift and automatically apply the trucks rear service brakes if the pressure decreases to the