TUBE ASSEM. 9F2693 - Caterpillar

Lower all implements to the ground in a stable position and move control lever back-and-forth through OPERATE and HOLD positions to eliminate any pressure oil in the cylinder lines. Personal injury could result from implement movement or oil spray while lines are being loosened to insert the covers.
Test 26Place all control levers in HOLD position, fully open the manual load valve, and then start the diesel engine. Record oil temperature. Tests 27 through 32Conduct these six tests in a similar manner. With manual load valve fully open, move control lever to LOWER position. Slowly close the manual load valve to obtain 1000 PSI, stabilize engine speed at 2000 (1800 or 1900) RPM. Record oil flow rate.Repeat this procedure for RAISE, DUMP, TILTBACK, auxiliary circuits' RETRACT and EXTEND control lever positions. Test 33Record oil temperature.Compute the cylinder leakage rate and the control valve leakage rate using your test data from the System Tests, Pump Test and Block Cylinder Tests.Example: Compute the lift LOWER circuit leakage rates.Test 15-flow rate of only the pump.Test 27-flow rate of pump and control valves.Test 4-flow rate of pump and control valve and cylinders.The system components being tested in Tests 15 and 27 are the same except for the control valves. Then the difference in flow rates (from the test data for Test 15, subtract the test data for Test 27) must be the leakage due to the control valves in the circuit.The system components being tested in Tests 27 and 4 are the same except for the cylinders. Then also, the difference in flow rates (from the test data for Test 27, subtract the test data for Test 4) must be the leakage due to the cylinders in the circuit.Compare the recorded test values with those listed in Chart C. Chart C data is maximum allowable for peak performance. Trouble Shooting PROBLEM: Tests 27 through 32 indicate leakage in one or more of the cylinders. PROBABLE CAUSE:A -Only one of a pair of cylinders in a circuit is leaking.B -Both cylinders of a pair in a circuit are leaking.C -Bucket positioner circuit is leaking. RECOMMENDED ACTION:Conduct the Right Hand Cylinder Blocked Test. PROBLEM: Tests 27 through 32 indicates leakage in the control valves. PROBABLE CAUSE:A -Maximum pressure relief valve leaking. B -Blown seals between control valve and tank.C -Make-up valves in all circuits are leaking.D -Cracked or worn control valve body and spools. RECOMMENDED ACTION:A -Remove the top from the hydraulic tank, drain a portion of the oil until the valve group is exposed. By running the engine at slower speeds (low idle to 1000 RPM) and operating the various circuits, the leak should be visible. (1P3519 Plastic Cover is available for some machines).B -Perform necessary repairs. PROBLEM: Tests 27 and 28 indicate leakage in LIFT control valve. PROBABLE CAUSE:A -Both LIFT circuit make-up valves leaking.B -Cracked or worn control valve body and spool in LIFT circuit.C -LIFT circuit check valve leaking. RECOMMENDED ACTION:Remove the top cover from hydraulic tank and visually check