SERVICE MANUALFig. 1 - Double Diaphragm Spring rake Chamber1 Push Rod2 Service Brake Chamber3 Spring Brake Chamber4 Spring Brake Push Rod Assembly5 Parking Brake Spring6 Breather Cap7 Release Bolt8 Push Rod springDESCRIPTIONThe double diaphragm spring brake chamberassembly consists of a tandem-type cylinder assemblyconnected to the foundation brake group either throughthe air brake slack adjuster or wedge assembly.The cylinder assembly consists of two basic sections.One section is a conventional service brake chamberwhile the second section is the spring (parking) brakechamber. The spring brake chamber contains apowerful spring which is completely compressed by airpressure in normal driving mode.OPERATIONNORMAL DRIVINGIn normal operation with the parking brake released (Fig.2) the spring brake control valve on the instrument panelmust be in the released position. When the control valveis in the released position, air pressure is permitted topass through the control valve and provide the springbrake chambers with air, thereby loading the springbrake chamber and compressing the parking brakespring, holding the rear wheel brakes in the releasedposition.Fig. 2 - Normal Driving PositionSERVICE BRAKE APPLICATIONWhen the service brakes are applied, air is forced intothe service brake chamber (Fig. 3) forcing the pushrodand piston assembly outward, extending the pushrodassembly.Fig. 3 - Service Brake ApplicationWhen the brake (foot) valve is released, air in the servicebrake system is exhausted and the service brakechamber pushrod assembly and diaphragm arepermitted to return to the normal released position. Thepushrod sprirg assists in this function by forcing thepushrod and plate assembly into the normal releasedposition.CTS-4101W - Page 3
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business
