Residual Air Check

Fig. 27 Installing Pressure Gauge:

The air dryer has a valve arrangement designed to maintain a minimum pressure in the shocks to improve ride characteristics under light load conditions. To check this function, proceed as follows:
1. Remove air line from dryer fitting and right shock absorber. Install a 0-300 psi pressure gauge inline, as shown.
2. Cycle ignition switch from OFF to ON.
3. Apply a load to rear suspension of 275-300 lbs. to run compressor and raise vehicle.
4. Remove load and allow the system to exhaust and lower.
5. When no more air can be exhausted, the gauge should indicate 10-22 psi.
6. Remove pressure gage then repeat steps 2 through 4 to ensure that system air pressure is in the shocks.