TM 5-3805-260-24CAUTION: Immediately after stopping the diesel engine,remove the Blocking Plate Assembly from the return lineon the control valve. This will prevent any possibledamage later.TroubleshootingPROBLEM: The percent of flow loss for Test 15 is10% or MORE. Flow differential for Test 15 is 2 gpmor MORE than flow differential for Test 17. Tests 18through 25 have the same flow differential.PROBABLE REASON:Oil aeration (low oil level, hydraulic oil that is not thecorrect type, air leak in the suction line for the pump, oilleaks in the tank such as failure of seals, looseconnections or pump cartridge is not installed correctly inpump body).RECOMMENDATION FOR ACTION:A. Check oil level and type of hydraulic oil beingused.B. Check suction line for air leaks [Put foam (likeshaving cream) on all connections. The foamwill be pulled into the line at any point ofleakage.]C. Remove cover from hydraulic tank and inspectfor oil leak (check above the oil level first).D. Disassemble pump and check for correctassembly.PROBLEM: Flow differential between each of theTests 18 through 25 suddenly becomeslower at one test and the flow rate isthe same for the remainder of the testsat higher engine speed (rpm).Example: 8 gpm differential betweenTests 18 and 19. 19 and 20, 20 and 21,but 1 gpm differential between 21 and22 and flow rates for Tests 23, 24 and25 are the same as 22.PROBABLE REASON:Pump cavitation (restriction in the suction line for thepump).RECOMMENDATION FOR ACTION:Inspect suction line and tank.BLOCKED CYLINDER TESTS (CHART C)If theSystem Tests and Pump Test give an indication ofleakage in the control valves and/orcylinders that is not acceptable, do the Blocked CylinderTests.Blocking Plate Assemblies or Caps and Plugs canbe put in each of the cylinder lines. For best accuracy,do these tests with the oil temperature approximately150° F (near the oil temperature for the System Testsand Pump Test).WARNING: Install the safety link. Lower allimplements to the ground. Move the steering wheel fromRIGHT TURN to LEFT TURN several times to releaseany pressure oil in the cylinder lines. All pressure in thelines must be released or injury to personnel anddamage to equipment can result while loosening thelines to install or remove the plate assemblies.All Cylinders Blocked1. Put control levers in HOLD position.2. Open the manual load valve fully.3. Start the diesel engine.Test 26: System Oil Temperature1. Turn the steering wheel to the RIGHT TURNposition.2. Run the engine at any rpm with the systempressure at 0 to 100 psi,3. Write down the oil temperature.Test 27 and 28: Leakage RatesThese two tests are similar. Do the tests as follows:1. With the manual load valve fully open, turn thesteering wheel to the RIGHT TURN position.2. Run the engine at test rpm.3. Slowly close the manual load valve to get 1000psi pressure.4. Write down the flow rate (gpm).5. Do this procedure again in the LEFT TURNposition.Test 33: System Oil Temperature1. Turn the steering wheel to the RIGHT TURN position.2-122
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