BOLT 4V4043 - Caterpillar

Personal injury can result from contact with hot hydraulic oil and from contact with hydraulic oil that is under high pressure.Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. The hydraulic oil pressure must be released before any service on the hydraulic system is performed or serious personal injury could occur.Verify that all of the work tools have been completely lowered to the ground. Release the hydraulic oil pressure at the hydraulic tank through the breaker relief valve when the breaker relief valve is cool enough to touch with your bare hand. Verify that the hydraulic oil is cool before you begin to remove any hydraulic components or hydraulic lines.
Note: Use the following procedure to check the low-pressure standby of the pumps.
Start the engine.
Run the engine at high idle.
Warm the hydraulic oil to normal operating temperature. Normal operating temperature is 45° C (113° F) to 60° C (140° F).
Illustration 1 g01163546
(1) Hydraulic lockout control in the LOCKED position.
Do not operate any implements during this test. Leave hydraulic lockout control (1) in the LOCKED position throughout this test. When hydraulic lockout control (1) is in the LOCKED position, the implements will not function.
Illustration 2 g02599798
Initial IQAN display
Illustration 3 g02601697
Press button (2) in order to activate the "Main" menu. Press button (3) in order to view the system pressures. Note: A manual pressure gauge can be used to check the standby pressure for the travel pump and the implement pump. Connect the pressure gauge to the pressure taps that are located on the pumps.
Record the reading on the display. The standby pressure for the travel pump and the implement pump should be 4000 kPa (580 psi). If the pressure is incorrect, adjust the differential relief valve.