TM 5-3805-260-24HYDRAULIC SYSTEMThe 5S5123 Hydraulic Testing Group is used tomake the pressure test of the hydraulic system. Beforeany tests are made, visually inspect the completehydraulic system for leakage of oil and for parts thathave damage. For some of the tests, a timer and ameasuring rule (either for inches or for millimeters) areusable tools.WARNING: When testing and adjusting thehydraulic system, move the machine to a smoothhorizontal location. Move away from machines that are atwork and any personnel. There must be only oneoperator. Keep all other personnel either away from themachine or where the operator can see the otherpersonnel.VISUAL CHECKSA visual inspection of the hydraulic system and itscomponents is the first step when a diagnosis of aproblem is made. Stop the engine, lower the bowl to theground and when the oil is cool so any pressure in thetank will be at a minimum, make the inspections thatfollow:1. Measure the oil level. Slowly turn the filler cap untilit is loose to let the tank pressure lower before the fillercap is removed. Look for air in the oil in the tank.2. Remove the filter element and look for particlesremoved from the oil by the filter element. A magnet willseparate ferrous particles from non-ferrous particles(piston rings, O-ring seals, etc.).3. Check all oil lines and connections for damage orleaks.OPERATION CHECKSChecks of scraper operation can be used to find thesource of oil leakage in the hydraulic system. The oil inthe hydraulic system must be at an operatingtemperature of 100° to 1200F (380 to 400C).Drift of Bowl CylindersCheck the drift of the bowl cylinders. Lift the bowl 6to 10 in. (152 to 254 mm), then move the control lever tothe HOLD position. After three minutes, put a mark onthe side of the bowl at the bottom of the draft arm 6 in.(152 mm) from the front of the bowl side. After fiveminutes, make the measurement for drift. Drift on a newmachine is not more than .31 in. (7.9 mm).If the drift is too much:1. Check the carry check valves.2. Check the piston seals in the bowl cylinders.MEASURING DRIFT UOF BOWL CYLINPUEHR(Typical Example)Travel Time of Bowl CylindersLower the bowl to the ground. Run the engine at highidle rpm. Use a stop watch to find the time needed tofully lift the bowl.The time to lift the bowl from the ground tomaximum height is approximately 2 seconds.If the travel time is not correct:1. Check pump efficiency.2. Check the settings of the relief valve for the bowland ejector circuits.3. Check the operation of the bowl valve spool in thecontrol valve for the scraper.4. Check the piston seals in the bowl cylinders.Drift of Door CylinderThe check valve for the door lets oil go to the ejectorcylinder and the door cylinder while the ejector moves.The check valve keeps the door closed at the time thebowl is loaded.If the door opens during the load operation:1. Check for dirt under the check valve.2. Check for a broken valve spring in the checkvalve.3. Make sure valve moves freely in the valve body.Travel Time of Ejector and DoorLift the bowl approximately 6 in. (152 mm). Makesure the door is closed. Run the engine at high idle.Hold the ejector control lever in the FORWARD position.Use a stop watch to find the time to fully open the doorand to move the ejector forward.4-25
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business