TM 5-3805-258-24-1A I R S Y S T E M A N D B R A K E SS Y S T E M S O P E R A T I O Nsion engages before the wheelThis action keeps the machinebrakes are released.from free movement(rolling) when the machine is on a slope.The emergency and parking brake is controlledmanually by the knob directly under the steeringwheel. The brake will operate automatically if the airpressure in the system gets too low.The brake system is divided into four differentcircuits: air supply for the air system, air circuit forthe emergency and parking brake, air circuit for thewheel brakes and hydraulic circuit for the wheelbrakes. The brake system is separated into these fourparts to make its explanation easier.The air supply provides the air under pressure tooperate the brake system. Air compressor (21), gover-nor (20) and air reservoir (8) and its valves make upthe air supply. On models 950BNSCE and 950BSCE,air dryer is also a component of the air supply.The air circuit for the emergency and parkingbrake provides protection for the machine if there is afailure in the air system. Emergency and parkingbrake (15) and its brake chamber (14), quick releasevalve (16), air pressure switch (5) and control valve(3) are components of this circuit.The air circuit for the wheel brakes sends airto operate the air horn and to activate the hydrauliccircuit for the wheel brakes. The components ofthe air circuit for the wheel brakes are: horn valve(10), air horns (9), air pressure switch (2) for wheelbrakes, left pedal (12) and its brake control valve(11), right pedal (30) and its brake control valve(29), orifice check valve (33), double check valve(32), air pressure switch (31) for stop lights, andtwo air cylinders [part of air/hydraulic cylinders(22) and (26)].The hydraulic circuit for the wheel brakes en-gages the wheel brakes when the air circuit causesbrake fluid pressure in the hydraulic circuit. Thecomponents of the hydraulic circuit are: two mastercylinders [part of air/hydraulic cylinders (22) and(26)], two brake fluid reservoirs (23) and (27), brakefluid pressure (overstroke) switches (25) for wheelbrakes and four wheel brakes (34).WARNING SYSTEMWhen the engine is running, loss of brake air pres-sure will cause brake air pressure indicator (4) andmaster fault light (1) to come ON, the fault alarmwill sound and the emergency and parking brake willautomatically engage.M A S T E R F A U L T L I G H T1. Light.When the emergency and parking brake is en-gaged, and the transmission is disengaged, parkingbrake indicator (3) will come ON. When the trans-mission is engaged and the emergency and parkingbrake is engaged, parking brake indicator (3) andmaster fault light (1) will come ON, and the faultalarm will sound. Also, when the transmission isengaged and the parking brake is engaged, the trans-mission neutralizer group automatically disengagesthe transmission.Too much master cylinder stroke (loss of hydraulicpressure) in the front or rear hydraulic circuit willcause brake fluid pressure indicator (2) and masterfault light (1) to come ON, and the fault alarm willsound.W A R N I N G I N D I C A T O R S2. Brake fluid pressure indicator. 3. Parking brake indica-tor. 4. Brake air pressure indicator.3-71
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business
