TM10-3930-660-20 12-8. SERVICE  BRAKE  HYDRAULIC  ACCUMULATOR  - REPLACE/REPAIR/TEST (Cont'd) Support accumulator (1) so it does not drop when clamps (4) are removed. It is not necessary to disconnect hydraulic hose (2) from accumulator (1) when testing or adjusting accumulator precharge pressure. 2. REMOVE CLAMPS (4) SECURING SERVICE BRAKE HYDRAULIC ACCUMULATOR (1) TO CAB AND LOWER SERVICE BRAKE HYDRAULIC ACCUMULATOR (1) TO THE GROUND. 3. INSTALL CHARGING AND GAUGING ASSEMBLY To SERVICE BRAKE HYDRAULIC ACCUMULATOR (1) . a. Remove outer gas valve cap (6) and inner gas valve cap (7) from accumulator (l). Do not connect nitrogen bottle to charging and gauging assembly at this time. b. c. Install charging and gauging assembly in place of cap (7) on accumulator  (l). Open isolator valve on charging 4. and gauging assembly by turning valve clockwise to a full stop. DEPRESS AND HOLD PUSHBUTTON ON TOP OF CHARGING AND GAUGING ASSEMBLY UNTIL PRESSURE READING IS OBTAINED ON GAUGE  . The pressure reading obtained in step 4 is the accumulator precharge pressure. This reading must be 700 psi + 50. 12-26