BENDIX BW2763 User Manual

Bendix® AD-SP® Air Dryer System

Field Inspection

1. Chock the vehicle wheels. Start the engine and charge the air brake system to governor cut-out, around 130 psi.

2. The primary and secondary air gauges will start to rise. As the system pressure reaches the cut-out pressure, the gauges will stop moving and the air dryer will purge. When the air dryer purges, the secondary gauge will drop 8 to 14 psi.

3. Shut off the engine and push in the yellow button to release the parking brakes. Note that the gauges will drop a small amount. Check the air gauges and if either gauge indicates a continued loss of pressure, check the system for leaks.

4. Apply and hold the service brakes by fully depressing the brake pedal. The gauges will drop a small amount. Again, check for a loss of pressure by watching both gauges. If either gauge indicates a continued loss of air pressure, check the system for leaks.

5. Release the service brakes. Continue to apply and release the service brakes until the pressure drops below governor cut-in (approximately 100 psi). Both gauges will show a drop in pressure with each brake application. If the system air pressure goes below 60 psi, the low pressure indicators will activate.

AD-SP® Air Dryer

Purge Cycle

6. Start the engine and charge the air brake system again. Turn the engine off.

7. Locate and drain the primary reservoir. Both dash air gauges will indicate a pressure drop. The secondary reservoir, which is not being drained, will stop showing a drop in pressure above 90 psi. If both continue to drain, this indicates that the secondary reservoir has a defective, or missing, pressure protection valve such as the SC-PR™ single check protection valve.

8. Install or service the SC-PR™ single check protection valve in the air brake system as shown in the schematic below.

9. Start the engine and charge the air brake system again. Turn the engine off.

10. Locate and drain the secondary reservoir. As this reservoir is drained, only the secondary gauge should indicate a pressure drop. If both continue to drain, this indicates that the primary reservoir has a defective, or missing, single or one way check valve.

11. Replace the existing, or install a new, single check valve in the primary reservoir supply port.

WARNING: Be sure to follow all the General Safety

Guidelines outlined in the AD-SP® Service Data Sheet,

SD-08-2415, before performing any service on the air

brake system.

Primary

Control Port

Turbo Cutoff

Governor

Engine Turbo Exhaust

Compressor

Port

Delivery

Port

™

Single Check Protection Valve

SC-PR

Reservoir

Supply

Reservoir

Secondary

Reservoir