WASHER 4814220 - Caterpillar

Personal injury can result from hydraulic oil under pressure.Hydraulic oil under pressure can cause injury to persons on or near the machine when the pressure is suddenly released.At operating temperature, the hydraulic oil tank is hot and under pressure. Hot oil can cause burns.Remove the fill plug only when the engine is stopped, and the fill plug is cool enough to touch with your bare hand.Do not allow hot oil or components to contact skin.
Personal injury can result from spring force released when removing cap screws.Internal spring force will be released when cylinder assembly cap screws are removed causing injury.Always restrain cover as cap screws are loosened.Follow the established procedure in the Service Manual to service these parts.
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the machine. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids.Dispose of all fluids according to local regulations and mandates.
Refer to the Systems Operation, Testing and Adjusting, "Machine Preparation for Troubleshooting".
Table 1
Required Tools
Tool Part Number Description Quantity
A 198-4240 Digital Pressure Indicator 1
Illustration 1 g01305708
Rear of Tractor (Left Side)
(1) Test Port
(2) Main relief valve coverThe main relief valve is a part on the main control valve for the scraper. The main relief valve is located near the oil line connection from the pump.Do the following procedures to check the pressure of the main relief valve.
Remove dust cap from fitting (1) and attach Tooling (A).
Start the engine. Run the engine at high idle rpm. Look at the pressure gauge. Move the joystick to the bowl RAISE position. The high reading on the digital pressure indicator is the pressure setting of the main relief valve. The correct pressure setting is 13300 kPa (1929 psi) to 14300 kPa (2074.1 psi) when the cylinder is at the end of stroke.
Illustration 2 g01305876
(2) Main relief valve cover
(3) Spring
(4) Stem
(5) Shims
If it is necessary to change the setting of the main relief valve, stop the engine. After approximately 5 minutes, remove cover (2) from the main relief valve. Remove shims (5) to decrease the pressure setting of the main relief valve. Add shims (5) to increase the pressure setting of the main relief valve.
Table 2
Change to Relief Valve Pressure (Addition or Removal of One Shim)
Part Number of Shims Thickness Change
5J-2721 0.13 mm (0.005 inch) 130 kPa (18 psi)
5J-2722 1.22 mm (0.048 inch) 1225 kPa (178 psi)
Remove the test equipment.