Diesel motor homes that include an air suspension system require a start up procedure different from the usual 'turn the ignition and go.' Suspension in this type of chassis is inflated by air bags. The number of air bags can total four or eight. Tag axle systems have ten air bags. It is important to remember that the air suspension system requires time to inflate before you drive off down the road. Tag axles generally need more time to pressurize than the four or eight bag air system.

On the cockpit dash there is one pressure gauge with two needles, or two gauges with one needle, and this is used to monitor air pressure in the front and rear tanks. After engaging the ignition, watch the oil pressure gauge and the air pressure gauge(s). When the system reaches full air pressure a 'pop,' similar to the sound of opening a can of soda, will emanate from the rear of the chassis to indicate the system is fully aired to ride height.

Once the air pressure gauge needles have reached full pressure, leave the engine running, and after assuring that the park brake is set, walk the exterior of the RV to the back end. Examine the mud flap. When the coach is fully aired and ready for travel there should be approximately two inches of clearance between the ground and the bottom of the mud flap.

Due to the weight of the RV, proceed with caution when driving over speed bumps. Decelerate to 5 mph or slower. Slow speeds will help to prevent the abrupt drop of a speed bump at the rear of the coach. Ground to chassis contact with excess force can damage expensive undercarriage and drive train components.

You may encounter an instance when turning the front wheels results in the wheels coming into contact with fiberglass. This generally occurs when the coach is not at proper ride height. Always keep the motor home ride height control valve to the specifications set by the manufacturer. Altering the ride height will affect suspension. Raising or lowering the air bags even as little as one inch can make a big difference in important chassis functions, such as driveline angles. If in doubt about accuracy of the settings, contact Technical Support for assistance.