CORE ASSEM. 7L4215 - Caterpillar

Table 7
Test Results Most Probable Causes
Drifting occurs only in Tests No. 1 and/or No. 3. Leakage between tilt valve spool and body (HOLD position)
Drifting occurs only in Tests No. 2 and No. 4 The load check valve is leaking.
The flow control valve is leaking.
Leakage between tilt valve spool and body (TILT RIGHT and TILT LEFT positions)
Drifting occurs in Tests No. 1, No. 2, No. 3, and No. 4 Leakage between pistons and cylinders
Leakage between tilt valve spool and body (all positions) Note: Remember that an O-ring seal failure in the circuit has the same effect as a major component failure.Lift Cylinders Drift Tests for the Ripper
Measure the ripper lift cylinder rod drift by using the following procedure:
Start the engine. Warm the hydraulic oil, as required.
Select the appropriate time, for the temperature of the hydraulic oil, in Table 8.
Position the ripper so that the lowest point on the ripper is approximately 300 mm (12 inch) above ground level. Position the tip cylinders at midstroke.
Measure the distance of the cylinder drift. The cylinder drift should not be more than 10 mm (0.39 inch) for the selected time. Note: The drift distance in the table is for new machines.
Table 8
Ripper Lift Cylinder Drift
Oil Temperature 28° to 48°C (83° to 118°F) 49° to 68°C (120° to 155°F) 69° to 88°C (156° to 190°F)
Must not move more than 10 mm (0.39 inch) 5 minutes 2.7 minutes 1.7 minutes Note: If excessive cylinder drift is noted, run the following tests in order to determine the cause.Tests
Raise the rear of the machine off the ground by lowering the ripper. Put the ripper control lever in HOLD position. Shut off the engine and watch the ripper lift cylinder rods for movement.
Raise the rear of the machine off the ground by lowering the ripper. Shut off the engine. Turn the key to the ON position. Put the ripper control lever in the LOWER position. Note: The accumulator for the pilot oil will supply pilot oil for 2 minutes. As a result, for Test 2 only use the 1.7 minute value in Table 8.
Raise the ripper off the ground. Put the control lever in HOLD position. Shut off the engine and watch the ripper lift cylinder rods for movement.
Raise the ripper off the ground. Shut off the engine. Turn the key to the ON position. Put the control lever in the RAISE position. Note: The accumulator for the pilot oil will supply pilot oil for 2 minutes. As a result, for Test 4 only use the 1.7 minute value in Table 8.
Table 9
Test Results Most Probable Causes
Drifting occurs only in Tests No. 1 and No. 3. Leakage between ripper lift valve spool and body (HOLD position)
Drifting occurs only in Test No. 2. and No. 4 The load check valve is leaking.
The flow control valve is leaking.
Leakage between ripper lift valve spool and body (RAISE and LOWER positions)
Drifting occurs only in Test No. 3 and No. 4. The makeup valve is leaking.
Leakage between ripper lift valve spool and body