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Air System
R-4 Preventive Maintenance
Every 25,000 miles, 3 months, or 900 operating hours, check for proper operation.
Every 100,000 miles, 12 months, or 3,600 operating hours, disassemble and rebuild the valve.
R-4 Operational and Leakage Tests
1. Chock the wheels, fully charge the air system, and adjust the brakes.
2. Make several brake applications and check for prompt application and release at each wheel.
3. With the parking brake applied, check for inlet valve and O-ring leakage. Coat the exhaust port
and the area around the retaining ring with a soap solution. A 1" bubble in 3 seconds is permitted.
4. With the parking brake released, check for exhaust valve leakage. Coat the exhaust port with a
soap solution. Maximum permissible leakage is a 1" bubble in 3 seconds.
5. Coat the outside of the valve where the cover joins the body to check for seal ring leakage. No
leakage is permitted.
6. Disconnect the line from the balance port. Release the parking brake and coat the balance port
with a soap solution to check the diaphragm and its seat. Leakage equivalent to a 1" bubble in 3
seconds is permitted.
If the valve does not function properly or if leakage is excessive, Bendix recommends that it be replaced
or rebuilt.
R-4 Removal
1. Block and hold the vehicle in position by means other than the air brakes.
2. Drain air brake system reservoirs.
Do not attempt to remove the inlet/exhaust valve without first draining
the entire air system to zero psi.
3. If the entire valve is to be removed, mark the air lines to make reinstallation easier. Before disas-
sembling, remove as much contamination as possible from the valve’s exterior, taking care to
keep all contamination from entering the open ports.
4. Disconnect air lines from valve.
It is generally not necessary to remove the entire R-14 valve in order
to service the inlet/exhaust valve. The inlet/exhaust valve insert can be
removed by removing the snap ring, exhaust cover assembly, and then
the inlet exhaust valve.
5. Remove valve mounting bolts and then the valve.
Summary of Contents for LOW FLOOR
Page 18: ...Specifications 18...
Page 58: ...Preventive Maintenance 58...
Page 110: ...Engine 110...
Page 138: ...Transmission Driveline Rear Axle 138...
Page 182: ...Suspension 182...
Page 260: ...Air System 260...
Page 420: ...Electrical System 420 Deutsch DT Series Connectors...
Page 421: ...Electrical System 421...
Page 422: ...Electrical System 422 Deutsch HD 10 Series Connectors...
Page 423: ...Electrical System 423...
Page 424: ...Electrical System 424 Deutsch HD 30 Series Connectors...
Page 425: ...Electrical System 425...
Page 442: ...Heating Air Conditioning 442...
Page 492: ...Body and Interior 492 Figure 11 33 USSC Seat Assembly...
Page 493: ...Body and Interior 493 Figure 11 34 USSC Seat Suspension Assembly...
Page 495: ...Body and Interior 495 Figure 11 37 Seat Air Connections...