BENDIX BW2077 manual Braking System Protection, Roadside Inspection, Temporary AIR Dryer Bypass

AD-IS®

AIR DRYER

GOVERNORS

ARE NON-

ADJUSTABLE

AND FEATURE A

BREATHER VALVE

IN THIS PORT

PRESSURE

PROTECTION

VALVE

LOCATIONS

FIGURE 4- PRESSURE PROTECTION VALVE LOCATIONS

WARNING:

DO NOT ATTEMPT TO ADJUST OR

SERVICE THE PRESSURE PROTECTION

VALVES. INCORRECT PRESSURE PROTECTION VALVE SETTINGS CAN RESULT IN AUTOMATIC APPLICATION OF VEHICLE SPRING BRAKES WITHOUT PRIOR WARNING.

TESTING THE AD-IS®EVERFLOW™ ASSEMBLY

Before placing the vehicle in service, perform the following tests.

1.Close all reservoir drain valves.

2.Build up system pressure to governor cut-out and note that one AD-IS®air dryer purges with an audible burst of air, followed immediately by approximately 30 seconds of air flowing out of the purge valve.

3.“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 a purge at the other AD-IS®air dryer exhaust.

4.It is recommended that the total air system be tested for leakage to assure that the AD-IS®air dryer will not cycle excessively.

See Bendix publication BW5057 “Air Brake Handbook" for additional information.

BRAKING SYSTEM PROTECTION

The AD-IS®EverFlow™ assembly allows the system to maintain one brake circuit up to about 100 psi even after a pressure loss in the other brake circuit. This allows a vehicle to be moved (in an emergency), but with reduced braking capacity. Compare this to a conventional system where a loss of pressure in one service tank leaves the

vehicle with a limited number of reduced braking capacity applications before the parking brakes automatically apply and stay on.

ROADSIDE INSPECTION

In the event of a roadside inspection the system behavior will be as follows: When the system is charged to governor cut-out, and then one reservoir drain valve is opened, initially both reservoir gauges will fall, however, the AD-IS®EverFlow™ assembly primary and secondary pressure protection valves will close at pressures above 70 psi, protecting the remaining brake circuit from further loss of pressure.

TEMPORARY AIR DRYER BYPASS

To temporarily bypass the EverFlow™ assembly, the following procedure needs to be followed.

Follow the General Safety Guidelines outlined on pages 5-6 in this document.

Make sure that all residual pressure has been released and the air dryer purge reservoir has been drained to 0 p.s.i., then remove the air supply line from the compressor to the inlet port (1 IN). Remove the safety valve from the AD-IS®air dryer body (see Figure 1 for location). Note that a short puff of trapped air may vent from the safety valve port when the valve is being removed. Install a T-fitting into the port. Using any adapters necessary, reinstall the safety valve in one of the branches of the T-fitting. Using any adapters necessary, install the air supply line into the remaining T-fitting port. After testing the T-fitting for any air leakage, by using a soap solution after charging to system cut-out pressure (a 1” bubble in 10 seconds is acceptable), the vehicle may be returned to temporary service.

Note: This is a temporary bypass of the air dryer, and full repair of the unit must be carried out at the earliest opportunity. With the EverFlow™ assembly removed from the system, contaminants will be entering the air system: reservoirs will need to be manually drained daily until the repairs are completed. At end of each working day, park vehicle and slowly drain pressure through the drain valves – leave open to the atmosphere, for several hours if possible. When repairs are carried out, be sure to check that all reservoirs (including the air dryer purge reservoir) are emptied of all contaminants.

If after bypassing the EverFlow™ assembly the system pressure still does not build, use the following procedure to remove, clean and reinstall the delivery check valve.

DELIVERY CHECK VALVE CLEANING PROCEDURE

(Note: This is only required if system pressure does not build after temporary bypass is completed.)

Refer to Figure 6 throughout this procedure. Depressurize the air brake system following the General Safety

7