86
Air System
SUSPENSION AIR SySTEM OPERATION
The major air components of the suspension system include the air springs and height control valves.
See Figures 6-
1 and 6-2. The system operates automatically to maintain a constant ride height regardless
of load or load distribution.
The pressure in the air spring bellows is varied automatically by the height control valves in proportion
to the coach load. Three height control valves, one at the front axle and two at the rear axle, maintain the
constant ride height under all load conditions.
The accessory air tank supplies compressed air to the height control valves. A pressure protection valve
allows removal of air from the accessory air tank only if pressure in the accessory tank is greater than
65 psi (450 kPa). A check valve at the accessory tank prevents the loss of air back into the main system.
An air strainer is also installed in the line with the pressure protection valve. The height control valves
meter air into the air spring bellows as needed. The valves are actuated by the relative movement be-
tween the coach body and the axles.
Never get under the coach without first blocking the frame or placing
the coach over a pit. With the air springs deflated there is not enough
clearance under the coach body for a person. When blocking the
body, place blocks under the chassis frame rails near the axles to be
serviced. Refer to the “Jacking and Towing Instructions” in the General
Information chapter of this manual.
As the coach is loaded the body settles toward the axles. This movement operates the height control
valve and air is allowed into the air springs. Air pressure in the air springs increases enough to compen-
sate for the additional load, which keeps the coach body at normal ride height.
As passengers leave the coach, the height control valves allow air to exhaust from the air springs. The
air in the air springs is reduced by the valves in proportion to the weight debarking the coach, which,
again, keeps the coach body at normal ride level.
The height control valves are designed to operate only when the load in the coach is changed. They do
not respond to the rapid relative motion between the axle and body such as that motion caused by road
bumps.
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...