AIR LINE FITTING....WHERE?

[KAYERIVERCITY]

GUYS.... I NEED TO ADD AN PRESSURIZING FITTING TO THE AIR BRAKE SYSTEM ON THE VOLVO TO KEEP THE MAXI'S RETRACTED EVEN IF THE PRESSURE DROPS OFF OVER THE WEEK END OR SO....WHERE DO I TAP INTO THE SYSTEM TO ADD A QUICK CONNECT AND A VALVE TO SHUT OFF THE QUICK CONNECT IF IT STICKS OPERN....ANY IDEAS?....WHAT I NEEED IS SOMETHING LIKE THE FIRE DEPARTMENT USES TO KEEP THE AIR SYSTEM FULL FOR IMMEDIATE/EMERGENCY RUNS ON THEIR AIR BRAKE PUMPERS.....GEOF