Re: 94 GM Air Springs
I think it would be a good idea to take it to the dealer for replacement. Here's the instructions from the manual The refill procedure uses a special Star tester to finish the job. That's about all I can help with since I only worked on te Police versions and have no experience with the air suspension.
SPECIAL SERVICE TOOL(S) REQUIRED
Air Spring Removal Tool T90P-5310-A
1.Turn air suspension switch OFF.
2. Raise vehicle on a hoist as outlined. Suspension must be fully down with no load. All 4 wheels
3. Remove heat shield as required.
4. Remove spring retainer clip.
DO NOT REMOVE AN AIR SPRING UNDER ANY CIRCUMSTANCES WHEN THERE IS PRESSURE IN THE AIR SPRING. DO NOT REMOVE ANY COMPONENTS SUPPORTING AN AIR SPRING WITHOUT EITHER EXHAUSTING THE AIR OR PROVIDING SUPPORT FOR THE AIR SPRING.
5. Remove air spring solenoid valve.
6. Remove spring piston-to-axle spring seat.
Insert Air Spring Removal Tool T90P-5310-A between axle tube and spring seat on forward side of axle. Position tool so that its flat end rests on air spring piston knob. Push downward, forcing piston and retainer clip off of axle spring seat.
7. Remove rear spring.
1. Install air spring solenoid valve as outlined.
2. Install air spring into frame spring seat, taking care to keep solenoid valve air and electrical connections clean and free of damage.
3. Connect push on ring spring retainer clip to knob of spring cap from top side of frame spring seat.
4. Connect air line and electrical connector to solenoid valve assembly.
5. Install heat shield to frame rear spring seat, if required.
6. Align air rear spring piston to axle seats. Squeeze to increase pressure and push downward on piston, snapping piston to axle seat at rebound and supported by shock absorber.
Air rear springs may be damaged if suspension is allowed to compress before spring is inflated.
7. Refill air rear springs.