Brett Wolfe 1993 U240
1. Be on reasonably level ground. Block wheels so the coach can not move even with the parking brake off.
2. Start the engine and run until full air pressure is reached. Listen for the dryer to purge (about 120 PSI).
3. Shut off the engine.
4. Release the park brakes by pushing in the yellow button (make sure you don’t roll, do NOT apply the brake pedal).
5. After the initial pressure drop, the system should not lose more than 2 PSI per minute.
6. Apply the brake pedal firmly (still with the parking brake is OFF).
7. After the initial pressure drop, the system should not loose any more than 3 PSI per minute.
8. With the engine off and parking brake off, rapidly pump the brake pedal to bleed down the air supply. During this, you should watch for the warning light and buzzer at about 60 PSI and then the yellow button (parking brake) should pop out at about 30 PSI.
9. Restart the engine and build up the air again. While building up pressure check how long it takes for the pressure to go from 85 to 100 PSI at “cruising RPM”. It should be less than 45 seconds.