TM  10-3930-643-34 HYDRAULIC  SYSTEM  TROUBLESHOOTING  AND  MAINTENANCE.  (cont) 12-1. Hydraulic  System  Troubleshooting.  (cont) MALFUNCTION TEST  OR  INSPECTION CORRECTIVE  ACTION k. HYDRAULIC PUMP NOT DELIVERING OIL. Step 1. Check hydraulic pump to determine if it is rotating. If  necessary,  replace  hydraulic  pump,  refer  to  paragraph  12-2. Step 2. Check hydraulic pump to determine if it is malfunctioning or worn  out. Replace pump, refer to paragraph 12-2. l. OIL LEAKAGE AT HYDRAULIC PUMP. Step 1. Check for worn or damaged oil seals or preformed packing(s), refer to paragraph 12-2. Replace  seals  and  preformed  packings  prior  to  installation  of  pump. Step 2. Check  for  defective  mounting  of  preformed  packing(s),  refer  to paragraph  12-2. Replace  preformed  packings  prior  to  reinstallation  of  pump. 12-8