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| Illustration 1 | g00720642 |
Manifold (tractor) (3) is located on the right hand side of the ejector truck. | |
Note: For additional information on the location of other callouts, refer to the schematic in Systems Operation, "General Information".
Manifold (3) controls the connection of the brake pump to the rod end of ejector cylinder (5). The manifold is also used as a passage for flow to the head end of the ejector cylinder. The manifold also incorporates the test ports for the head end and the rod end for ejector cylinder (5) .
The manifold contains the following components: check valve, sequence valve and shuttle valve. The check valve prevents the ejector system from communicating back to the brake system. The sequence valve is used as a priority valve to ensure that the brake system always has sufficient pressure for proper brake performance. If the brake system has a pressure that is greater than 15858 kPa (2300 psi), then the sequence valve will open and this allows the ejector system to operate.
Shuttle valve (4) dictates when the sequence valve is allowed to open. By blocking the tank line of the sequence valve, the shuttle valve can cause the sequence valve to close or the shuttle valve can prevent the sequence valve from opening. The shuttle valve receives a pressure signal from the actuators on the ejector control valve. If ejector control valve (7) is in one of the following positions, shuttle valve (4) allows the sequence valve to open.
- EJECT
- RETRACT
- SUSPENSION RAISE
The shuttle valve will keep the sequence valve closed if the ejector control valve is in the HOLD position.