TM 10-3930-675-20-2 0050 00-4 Table 1. Preventive Maintenance Checks and Services (PMCS) for the RT 240 RTCH - Continued. Item No. Interval Man- Hours Item To Check/ Service Procedure Equipment Not Ready/ Available If: 12 Semi- annual (1000 Hours) Hydraulic System Breather Filters Replace  breather  filters  (WP  0183  00 and LO 10-3930-675-12). 13 Semi- annual (1000 Hours) Hydraulic Reservoir Return Filters Replace    return    filters    and    top    off hydraulic fluid (WP 0183 00). 14 Semi- annual Hydraulic System Ball Valves Open  and  close  to  ensure  easy  opera- tion. 15 Semi- annual (1000 Hours) Front Axle Brake Cooling Filters Replace front axle brake cooling filters (WP 0126 00 and LO 10-3930-675-12). 16 Semi- annual (1000 Hours) Front Axle Differential Housing and Hub End Drain  and  refill  front  axle  differential housing and hub end (LO 10-3930-675- 12). 17 Semi- annual (1000 Hours) Rear Axle Brake Cooling Filters Replace  rear  axle  brake  cooling  filters (WP 0126 00 and LO 10-3930-675-12). 18 Semi- annual (1000 Hours) Rear Axle Differential Housing and Hub End Drain  and  refill  rear  axle  differential housing and hub end (LO 10-3930-675- 12). 19 Semi- annual Front and Rear Axle Vent Hoses Inspect  for  plugged  hoses  and  valves. Clean if necessary. 20 Semi- annual Brake and Steering Accumu- lators Check pre-charging pressure (WP 0186 00). 21 Semi- annual Parking Brakes Perform   parking   brake   checks   (WP 0120 00). 22 Semi- annual (1000 Hours) Tophandler Gear Motors Drain  and  refill  oil  (LO  10-3930-675- 12).