BENDIX BW1664 manual Preventive Maintenance, Operation & Leakage Tests

	EXHAUST	EXHAUST
		SOLENOID
	DIAPHRAGM
EXHAUST PORT
		BRAKE VALVE
		SUPPLY
		SOLENOID
BRAKE	SUPPLY	SPRING
		SPRING
CHAMBER	DIAPHRAGM
FIGURE 7 - M-21™, M-22™MODULATOR ANTILOCK EXHAUST OF BRAKES

ANTILOCK RE-APPLY

If the antilock controller senses that wheel speed has increased sufficiently to require reapplication of braking pressure, it de-energizes the supply and exhaust solenoids. With both solenoids de-energized, the modulator re-applies air to the brakes in the same manner it did during a non- antilock application.

PREVENTIVE MAINTENANCE

GENERAL

Perform the tests and inspections presented at the prescribed intervals. If the modulator fails to function as described, or leakage is excessive, it should be replaced with a new or genuine Bendix remanufactured unit, available at any authorized parts outlet.

EVERY 3 MONTHS, 25,000 MILES OR 900 OPERATING HOURS

1.Remove any accumulated contaminates and visually inspect the exterior for excessive corrosion and physical damage.

2.Inspect all air lines and wire harnesses connected to the modulator for signs of wear or physical damage. Replace as necessary.

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3.Test air line fittings for excessive leakage and tighten or replace as necessary.

4.Perform the ROUTINE OPERATION AND LEAKAGE TESTING described in this manual.

OPERATION & LEAKAGE TESTS

LEAKAGE TESTING

1.Park the vehicle on a level surface and block or chock the wheels. Release the parking brakes and build the air system to full pressure.

2.Turn the engine OFF and make 4 or 5 brake applications and note that the service brakes apply and release promptly.

3.Build system pressure to governor cut-out and turn the engine OFF.

4.Make and hold a full service brake application.

A.Apply a soap solution to the exhaust port of the modu- lator. Leakage should not exceed a 1" bubble in less than 3 seconds. If leakage exceeds the specified maxi- mum, replace the modulator.

B.Apply a soap solution around the solenoid assembly (top and bottom). Leakage should not exceed a 1" bubble in less than 3 seconds. If leakage exceeds the speci- fied maximum, tighten the solenoid cap screws and re-test. If the leakage remains excessive after re-test- ing, replace the modulator.