2 - 78 SUSPENSION/DRIVESHAFTS

AIR LINE FITTINGS

To remove an air supply line from an air compressor assembly air line fitting. Push in (toward reciever dryer) on the plastic ring of the reciever dryer air supply air line fitting. While holding in the air line fitting on the reciever dryer pull the air supply line strait out of the fitting (Fig. 6).

Fig. 6 Release Air Line from Fitting

The fitting has a unique push-in feature. A brass type collet locks the air line in place. One rubber O-Ring seals the air line to prevent air leakage. To attach air line, just push into fitting (Fig. 7).

Fig. 7 Push Air Line into Fitting

AIR CHECK, RESIDUAL

The air dryer has a valving arrangement that maintains 172 to 276 kPa (25 to 40 psi).

To test this function, perform the following procedure:

(1)Remove the air line from the dryer and strut or spring. Attach a piece of bulk nylon tubing to one side of a Pressure Gauge (0-300 psi), and to the strut/spring solenoid (Fig. 8).

(2)Attach another piece of nylon tubing from the dryer (compressor) to other side of the pressure gauge.

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Fig. 8 Pressure Gauge Installed in System

A compression ball sleeve nut and sleeve for 3/16 inch tubing with ball sleeve connector and an internal pipe T-fitting. Can be used to attach the tubing to the pressure gauge.

(3) Activate compressor by grounding pin 508 to pin x 20 (See Control Module Connector), cycle unit and read actual air pressure. Pressure of 172 to 276 kPa (25 to 40 psi) indicates that the system and compressor is acceptable.

COMPRESSOR PERFORMANCE TEST

This test can be performed on the vehicle to evaluate compressor current draw, pressure output, and leak down.

(1)Disconnect the compressor motor wiring harness connector.

(2)Disconnect air line between dryer and strut or spring solenoid.

(3)Connect an air pressure gauge into the system (Fig. 8).

(4)Connect an ammeter in series between the red wire terminal on compressor connector and a 12 volt power source. Also, connect a ground wire from the black wire terminal on the compressor connector to a good ground on the frame (Fig. 9)

(5)If the current draw to the compressor motor exceeds 30 amperes, replace the compressor assembly.

AIR LEAK CHECK

(1)Check all air line to connector joints.

²Air line to compressor connectors.

²Air line to solenoid.

(2)Check the rubber membranes.

²Front struts.

²Rear springs.