BENDIX M-21-M-22 ANTILOCK MOD ASSY Manual de servicio descargar pdf (Pagina 17)

LEAKAGE TESTS

1. Build the air system pressure to governor cut-out. With the dash-mounted trailer

supply valve activated for tractor/trailer operation, apply a soap solution to all

three exhaust ports (two in cover and one in body). The leakage noted should not

exceed a one inch bubble in less than three seconds at any exhaust port.

2. Make and hold a full brake application and apply a soap solution to all three

exhaust ports and around the cover where it joins the body. The leakage noted

should not exceed a one-inch bubble in less than three seconds at any exhaust

port.

Antilock Modulator Valve

The antilock system modulator is essentially a high capacity, on/off air valve that

incorporates a pair of electrical solenoids for control. The solenoids provide the

Electro-pneumatic interface or link between the antilock controller electronics and the

air brake system. This valve can be used to control the braking function on an individ-

ual wheel or two service actuators. The modulator valve consists of a die-cast alu-

minum body and a solenoid assembly which contains one normally open solenoid

(NOS), one normally closed solenoid (NCS), and two inlet and exhaust diaphragm

valves. A weather-resistant electrical connector is an integral part of the solenoid

assembly and serves to carry control commands from the antilock controller modula-

tor valve. The single Supply, Delivery and Exhaust port on the valve is identified with a

cast, embossed numeral for positive identification.

OPERATION

Non-Antilock Applications

Curing normal non-antilock braking, both solenoids are de-energized (no electrical

power). Brake application air enters the Supply port of the valve and flows to and

through the open exhaust solenoid, then to the exhaust diaphragm. Air pressure along

with spring force seats the exhaust diaphragm on the exhaust passage, thus prevent-

ing the escape of service air. Simultaneously, application air flows to the supply

diaphragm and forces it away from its seat. Air flows past the open supply and out the

valve delivery port to the service brake chambers.

Non-Antilock Hold

When the desired air pressure is attained in the service brake chambers, the brake

system is in the Holding position. In the Holding position, both solenoids in the valve

remain de-energized and the balance of the internal components remain in the same

position as they assumed during application.

Air Brake System

Revised 11/15/99

1 2 ... 12 13 14 15 16 17 18 19 20 21 22 ... 31 32

Sin comentarios

BENDIX M-21-M-22 ANTILOCK MOD ASSY Manual de servicio Pagina 17