TM 10-3930-659-20 Table 4-3.  Hydraulic Troubleshooting (Con't). MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION 3.  STEERING OR HYDRAULIC FUNCTIONS ARE NONEXISTENT. Step 1.  Test main hydraulic pump flow (see paragraph 17-1). Replace damaged main hydraulic pump (see paragraph 17-6). Step 2.  Inspect hydraulic reservoir suction filter for restrictions. Drain hydraulic reservoir (see LO 10-3930-659-12), and clean or replace hydraulic reservoir suction filter (see paragraph 17-29). Step 3.  Remove main hydraulic pump (see paragraph 17-6) and inspect drive shaft for damage. If drive shaft is damaged, notify Direct Support Maintenance. 4.  STEERING IS NORMAL AND HYDRAULIC FUNCTIONS ARE NONEXISTENT. Test fork/brake hydraulic pump standby pressure (see paragraph 17-3). Adjust fork/brake hydraulic pump standby pressure (see paragraph 17-3) Replace damaged fork/brake hydraulic pump (see paragraph 17-5). 5.  ONE HYDRAULIC FUNCTION DOES NOT WORK. Step 1.  Test hydraulic cylinders for drift/leakage (see paragraph 17-4). Replace damaged hydraulic cylinder (see paragraph 17-9 or 17-32). Step 2.  Check forklift control valve for sticking or damage. Replace sticking or damaged forklift control valve (see paragraph 17-8). 6.  HYDRAULIC POWER IS LOW. Step 1.  Test hydraulic cylinders for drift/leakage (see paragraph 17-4). Replace damaged hydraulic cylinder (see paragraph 17-9 or 17-32). Step 2.  Test fork/brake hydraulic pump standby pressure (see paragraph 17-3). Adjust fork/brake hydraulic pump standby pressure (see paragraph 17-3). Replace damaged fork/brake hydraulic pump (see paragraph 17-5). 7.  FORK/BOOM DRIFTS. Step 1.  Test hydraulic cylinders for drift/leakage (see paragraph 17-4). Replace damaged hydraulic cylinder (see paragraph 17-9 or 17-32). 4-38