DRIVE GP-FINAL 3789568 - Caterpillar

Visual Checks
A visual inspection of the hydraulic system and its components is the first step when a diagnosis of a problem is made. Stop the engine, lower the blade to the ground and when the oil is cool so any pressure in the tank will be at a minimum, make the inspections that follow:1. Measure the oil level. Slowly turn the filler cap until it is loose to let the tank pressure lower before the filler cap is removed. Look for air in the oil in the tank.2. Remove the filter element and look for particles removed from the oil by the filter element. A magnet will separate ferrous particles from nonferrous particles (piston rings, O-ring seals, etc.).3. Check all oil lines and connections for damage or leaks.Checking Pump Efficiency
For any pump test at a given rpm, the pump flow (gpm) at 100 psi (690 kPa) will be larger than the pump flow (gpm) at 1000 psi (6900kPa).The difference between the pump flow of two operating pressures is the flow loss. Flow loss when expressed as a percent of flow loss is used as a measure of pump performance.If the percent of flow loss is more than 10% for test on the machine or 15% for test on the bench, pump performance is not good enough. Test On The Machine
Install a 9S2000 Flow Meter. Run the D6 Tractor engine at 2000 rpm (for D5 Tractor, 1750 rpm). Measure the pump flow at 100 psi (690 kPa) and at 1000 psi (6900 kPa). Use these values in Formula I. Test on the Bench
If the test bench can be run at 1000 psi and at full pump rpm, find percent of flow loss using Formula I.If the test bench can not be run at 1000 psi at full pump rpm, run the pump shaft at 1000 rpm. Measure the pump flow at 100 psi (690 kPa) and at 1000 psi (6900 kPa). Use these values in the top part of Formula II. For the bottom part of the formula, run the pump shaft, for D6 Tractor, at 2000 rpm (for D5 Tractor, 1750 rpm). Measure the pump flow at 100 psi. Operation Checks
Checks of implement operation can be used to help find the source of oil leakage in the hydraulic system. The oil in the hydraulic system must be at an operating temperature of 100° to 120°F (38° to40°C).Cylinder Drift
The temperature of the hydraulic oil has an effect on the amount of cylinder rod drift. Lift and lower the bulldozer (and the ripper if the tractor has one) many times to increase the temperature of the hydraulic oil in the cylinders and tank. Make a record of the hydraulic oil temperature.Lift the bulldozer (and the ripper) so it is approximately 10 inches (250 mm) off of the ground. With the control lever in HOLD position (and ripper control in HOLD position), stop the engine. Measure the lengths of the cylinder rods and make a record of each measurement. After 5