Brakes are not Applied
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| Illustration 1 | g00726325 |
Service Brake System with released brakes (1) Pressure plate (2) Brake disc (3) Brake disc (4) Piston (5) Pilot valve (6) Pressure switch (7) Brake cylinder (boost) (8) Brake cylinder (master) (9) Hydraulic tank (10) Brake reservoir (11) Joystick control (12) Universal joint shaft (A) Low pressure oil (B) Boost pressure oil | |
When the brake pedal is fully released, the piston in brake cylinder (8) and the piston in brake cylinder (7) are held stationary by spring force. Low pressure oil (A) holds pistons (4) slightly away from pressure plates (1) so that no force is applied to the brake disc packs. Brake discs (3) which are splined to universal joint shafts (12) rotate between brake discs (2) which are splined to the axle housing.
Boost pressure oil (B) from pilot valve (5) which is connected to the implement pilot system is blocked at the inlet port of brake cylinder (7). There is an open port in brake cylinder (8) and brake cylinder (7) which allows oil from brake reservoir (10) to top up the brake cylinders.
Pressure switch (6) for the transmission neutralizer is closed.
Brakes are Applied
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| Illustration 2 | g00726329 |
Service Brake System with applied brakes (1) Pressure plate (2) Brake disc (3) Brake disc (4) Piston (5) Pilot valve (6) Pressure switch (7) Brake cylinder (boost) (8) Brake cylinder (master) (9) Hydraulic tank (10) Brake reservoir (11) Joystick control (12) Universal joint shaft (A) Low pressure oil (B) Boost pressure oil (C) High Pressure oil (D) Pressurized oil from brake cylinder (master) | |
When the brake pedal is pressed, pressurized oil (D) is transmitted from brake cylinder (8) to the inlet port of brake cylinder (7). The pressurized oil offsets a plunger in brake cylinder (7). The initial movement of the plunger opens a port which allows boost pressure oil (B) from pilot valve (5) to act on the pistons in brake cylinder (7). The pressurized oil from brake cylinder (8) is assisted by boost pressure oil in order to offset the pistons which create high pressure oil (C) in the brake lines.
At the axles, pistons (4) force pressure plates (1) against the brake disc packs. Brake discs (3) which are splined to universal joint shafts (12) are forced against brake discs (2) which are fixed in order to prevent the shafts from rotating.
Pressure switch (6) for the transmission neutralizer is open. If the transmission neutralizer control (switch) on the dash panel is in the ON position, power is disconnected from the transmission control in order to disengage the transmission.
When the brake pedal is released, the piston in brake cylinder (8) moves backward. This relieves the pressure on the pistons in brake cylinder (7) which also move backward. Boost pressure oil is blocked at the inlet port for brake cylinder (7) and any boost pressure oil that remains is relieved to the hydraulic tank. As the pistons in brake cylinder (7) move backward, some of the oil in the brake lines is drawn back into brake cylinder (7) .
At the axles, pressure is relieved from the pistons and the pressure plates. The force against the brake disc packs is relieved and brake discs (3) which are splined to the universal joint shafts are free to rotate with the shafts.
Note: For additional information on the brake system, refer to Systems Operation, "General Information".