LINE A 9N1116 - Caterpillar

ReferenceRefer to Special Instruction, SEHS8979, "Component Identification and Calibration of the 1U5796 Differential Pressure Gauge Group" for more information on using Tooling (D) .Test Preparation
Refer to Testing and Adjusting, "Machine Preparation for Troubleshooting".Refer to Testing and Adjusting, "System Pressure Release".
Illustration 3 g03530063
Move steering frame lock to the LOCKED position.
Engage the parking brake. Move the transmission direction selector to the NEUTRAL position.Test Procedure
Attach a 0 to 60000 kPa (0 to 8700 psi) pressure gauge (D5) to the tee on pressure differential gauge group (D7) .
Illustration 4 g03446596
(2) Pressure tap for the steering pump. Cab Assembly removed for clarity.
Connect one end of hydraulic line (D1) to pressure tap (2). Pressure tap (2) is located on the panel for the remote pressure taps that is on the right side of the machine. Connect the other end of hydraulic line (D1) to the tee on pressure differential gauge group (D7) .
Illustration 5 g03446597
Right Side View of Steering HMU Metering Pump (3) HMU pump. (4) Pressure tap for signal pressure.
Connect hydraulic line (D1) between signal pressure tap (4) and the single pressure port on pressure differential gauge group (D7). Signal pressure tap (4) is located next to HMU pump (3). HMU pump (3) is located below the front of the cab.Note: Position pressure differential gauge group (D7) and hydraulic lines (D1) in order to prevent damage from any machine movement. Position the test equipment in order to allow a second technician to observe and record the pressure readings safely.
Start the engine. Operate the engine at high idle. Continuously stall the RACK BACK function while simultaneously raising the lift arms at full speed. When the lift arms are almost raised, cycle the tilt cylinder almost to the FULL DUMP position. Then move the tilt cylinders to the full RACK BACK position. Continuously stall the RACK BACK function and simultaneously lower the lift arms back to the ground level position. Without stalling the RACK BACK function, cycle the lift function to raise the lift arms fully. Then lower the lift arms in order to allow the pump to operate at low-pressure briefly and circulate oil through the system. Repeat this process in order to increase the temperature of the oil to normal operating temperature.
After the oil has reached normal operating temperature, lower the bucket to the ground. Stop the engine.
Move steering frame lock to the STORED position.
Start the engine. Raise the bucket until the bucket is slightly off the ground. Run the engine at high idle.Note: During the following steps, do not continue to turn the steering wheel once the machine ceases to articulate. Once the machine ceases to articulate in one direction, immediately turn the steering wheel in the opposite direction. Make sure that you turn the steering wheel at a constant rate. The pressure that is indicated on pressure gauge (D7) will vary with the speed of rotation. Slower rotation will cause a lower pressure reading. Faster rotation will cause a higher pressure reading.
Articulate the machine all the way to the left or all the way