BENDIX BW1450 manual Operation & Leakage Tests, Every 10,800 hours or 300,000 miles or 36 months

2.Check mounting bolts for tightness. Retorque to 270- 385 inch pounds.

3.Perform the Operation & Leakage Tests listed in this publication.

Every 10,800 hours or 300,000 miles or 36 months:

1. Rebuild the air dryer including the desiccant cartridge.

Note: The desiccant change interval may vary from vehicle to vehicle. Although typical desiccant cartridge life is three years, many will perform adequately for a longer period of time. In order to take maximum advantage of desiccant life and assure that replacement occurs only when necessary, it is important that Operation & Leakage Tests be performed.

WARNING!

This air dryer is intended to remove moisture and other contaminants normally found in the air brake system. Do not inject alcohol, anti-freeze, or other de-icing substances into or upstream of the air dryer. Alcohol is removed by the dryer, but reduces the effectiveness of the device to dry air. Use of other substances can damage the air dryer and may void the warranty.

OPERATION & LEAKAGE TESTS

1.Test the outlet port check valve assembly by building the air system to governor cut-out and observing a test air gauge installed in the supply reservoir. A rapid loss of pressure could indicate a failed outlet port check valve. (Note: Purge valve will be open when governor cut-out pressure is reached. Allow 45 seconds after governor cut-out occurs to complete the purge cycle before testing the check valve.) Coat the exhaust with a soap solution. Leakage should not exceed a 1" bubble in 1 second.

2.Check for excessive leakage around the purge valve. With the compressor in loaded mode (compressing air), apply a soap solution to the purge valve housing assembly exhaust port and observe that leakage does not exceed a 1" bubble in 1 second. If the leakage exceeds the maximum specified, service the purge valve housing assembly.

3.Close all reservoir drain cocks. Build up system pressure to governor cut-out and note that AD-4™air dryer purges with an audible escape of air. “Fan” the service brakes to reduce system air pressure to governor cut-in. Note that the system once again builds to full pressure and is followed by an AD-4™air dryer purge.

4.Check the operation of the safety valve by pulling the exposed stem while the compressor is loaded (compressing air). There must be an exhaust of air while the stem is held and the valve should reseat when the stem is released.

5.Check all lines and fittings leading to and from the air dryer for leakage and integrity.

6.Check the operation of the end cover heater and thermostat assembly during cold weather operation as follows:

A.Electric Power to the Dryer

With the ignition or engine kill switch in the ON position, check for power at the dryer’s electrical terminal using a voltmeter or test light. On a single terminal AD-4™air dryer’s disconnect the lead wire at the end cover terminal post. Place the test leads on the lead wire and a GOOD vehicle ground. On dual terminal AD-4™air dryer’s disconnect both lead wires at the end cover terminal posts. If there is no voltage indicated, look for a blown fuse, broken wires, or corrosion in the vehicle wiring harness. Check to see if a good ground path exists.

B.Thermostat and Heater Operation

Turn off the ignition switch and cool the end cover assembly to below 40 degrees Fahrenheit. Using an ohmmeter, check the resistance between the electrical terminal and the metal end cover (see Figure 5). (Note: On the dual terminal end cover, check the resistance between the two terminals.) The

HEATER POST	9		1
	8		9
A
			10
B			7
	THERMOSTAT		11
			6
	COVER		4
	1
		3	2
	5		1
	SINGLE WIRE SYSTEM
BOLD NUMBERS ARE ITEMS IN MAINTENANCE KITS
			1
			9
11			10
8			7
6
5			BOOT
4
3
2	CONNECTIONS FOR POWER
1
	BOOT	AND INSULATED RETURN
	DUAL WIRE SYSTEM

FIGURE 5 - AD-4™AIR DRYER SINGLE AND DUAL

TERMINAL THERMOSTAT ASSEMBLIES

5