TM 10-3930-659-20 Table 4-3.  Hydraulic Troubleshooting. MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION HYDRAULIC SYSTEM 1.  HYDRAULIC PUMP IS NOISY. Step 1.  Check for foamy hydraulic fluid and leaking hydraulic lines, hoses, and fittings. Tighten all lines, hoses, and fittings. Replace worn or leaking preformed packings, lines, hoses, or fittings (see paragraph 17-14, 17- 15, 17-16, 17-17, 17-18, 17-19, 17-20, 17-21, 17-22, 17-23, 17-24, 17-25, 17-26, 17-27, 17-37, 17-38, or 17-39). Step 2.  Inspect hydraulic reservoir-to-oil return filter line for restrictions or damage. Replace restricted or damaged hydraulic reservoir-to-oil return filter line and fittings (see paragraph 17-37). Step 3.  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 4.  Test fork/brake hydraulic pump flow (see paragraph 17-2). Replace damaged fork/brake hydraulic pump (see paragraph 17-5). Step 5.  Test main hydraulic pump flow (see paragraph 17-1). Replace damaged main hydraulic pump (see paragraph 17-6). 2.  HYDRAULIC FUNCTIONS ARE SLOW. Step 1.  Check for foamy hydraulic fluid and leaking hydraulic lines, hoses, and fittings. Tighten all lines, hoses, and fittings. Replace worn or leaking preformed packings, lines, hoses, or fittings (see paragraph 17-14, 17- 15, 17-16, 17-17, 17-18, 17-19, 17-20, 17-21, 17-22, 17-23, 17-24, 17-25, 17-26, 17-27, 17-37, 17-38, or 17-39). Step 2.  Check engine idle speed (see STE/ICE-R Test GO4). Step 3.  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). 4-37