TM10-3930-660-20 12-8. SERVICE  BRAKE  HYDRAULIC  ACCUMULATOR - REPLACE/REPAIR/TEST (Cont’d) 7.   REMOVE CHARGING AND GAUGING ASSEMBLY FROM SERVICE BRAKE  HYDRAuLIC ACCUMULATOR  (1)  . a. b. c. d. Close isolator valve by turning valve counterclockwise to a full stop. Remove charging and gauging assembly from accumulator (l). Install inner gas valve cap (7) and outer gas valve cap (6) to accumulator (l). Tighten outer gas valve cap to between 15 and 30 lb. ft. Brush a soap solution on and around outer gas valve cap (6) and verify that no air bubbles are  present. Air bubbles indicate nitrogen leakage. Correct any leakage before installing accumulator (1) to vehicle. 8. SECURE SERVICE BRAKE HYDRAULIC ACCUMULATOR (1) TO CAB WITH CLAMPS (4)  . 12-28