TM  10-3930-643-34 HYDRAULIC  SYSTEM  TROUBLESHOOTING  AND  MAINTENANCE.  (cont) 12-1. Hydraulic  System  Troubleshooting.  (cont) MALFUNCTION TEST  OR  INSPECTION CORRECTIVE  ACTION d. LOSS OF CYLINDER MOTION DURING OPERATION. Step 1. Check  hydraulic  pressure. If pressure is low, go to step 2. Step 2. Check hydraulic pump outlet to determine if it is operating correctly, refer to paragraph 12-2. If  necessary,  clean  the  hydraulic  line,  refer  to  TM  10-3930-643-20. Step 3. Check loader control valve relief valve(s) to determine if any are leaking and/or defective, refer to paragraph 12-3 for tests and  adjustments. If necessary, replace hydraulic pump, refer to paragraph 12-2. Step 4. Check loader control valve relief valve(s) to determine if any are leaking and/or defective, refer to paragraph 12-3 for tests and  adjustments. If necessary to repair system relief valve, refer to paragraph 12-3. If necessary to repair or replace circuit relief valve(s), refer to paragraphs 12-4, 12-5 and 12-6. Step 5. Check loader control valve system relief valve for broken spring, refer to paragraph 12-3. Replace spring, refer to paragraph 12-3. 12-4