LINES GP- 1966443 - Caterpillar

Brake Release and Duo-Cone Seal Test Power Unit Start-Up
Check the Seal Test System
Since this Power Unit is controlled by the same electronic system, it is not necessary to check motor rotation. Air pressure must be established to the air valve. A minimum of 20 psi (138 kPa) must be present. Pull the air hose from the Air Test Hose reel and hold. Press the "BRAKE AIR" button on the control pad. Air will flow from the air hose.
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Connect the Air Decay Blocking Valve to the air hose. Press the "BRAKE AIR" button (B) on the control pad.
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Air pressure will read out on the gauge display. Turn the valve to shut off pressure. Release the "BRAKE AIR" button.Brake Release Pressure System
This system provides brake release pressure to the Wheel Station Brakes. Brake release pressures vary on machine models 777-793, and range between 550 - 600 psi (3890 - 4134 kPa). It may be necessary to adjust the Brake Release pressure from one machine family component to another. This is adjusted at the relief valve on the Brake Release Power Unit.
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Adjustment ScrewTurning the adjustment screw (A) clockwise will increase the pressure. Counterclockwise will decrease the pressure.Oil from this system is filtered with a 3 micron medium pressure filter. It is then sent through the Brake Release Oil hose reel to the Brake Release Shut-off Valve Assembly. The fittings on this assembly may be changed to accept current fitting arrangements being used in this process.Check Brake Release Pressure and Function
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Make sure that the valved quick disconnects are attached to the brake pressure hose. Close the brake pressure release valve located on power unit.
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Press and hold the "Brake Fill" (F) button on the control pad.
The motor will turn on and the pressure will rise in the system. Observe the maximum pressure on the pressure gauge. The pressure should be set at 600 psi (4135 kPa).
Release the "Brake Fill" button. Release the pressure in the system by opening the Brake Release Pressure Valve.
Turn off the system by pressing the "OFF" button on the control pad.Duo-cone Seal Air Decay Test
Remove the cover plate from the Brake Cooling Inlet port. Replace it with the appropriate modified plate. Check for proper sealing of both plates.
Connect the Air Decay Test Valve Assembly to the Air hose.
Connect the Valve Assembly to the Brake Cooling Inlet plate. Open the needle valve. Activate the "BRAKE AIR" sequence either on the main control pad or the remote and hold until the gauge reads maximum pressure. This will allow the cavity to fill.
Once the cavity is filled and the pressure has stabilized to 20 psi (138 kPa), turn the needle valve clockwise to trap the pressure. Observe the pressure after five minutes. The pressure should not decay by more than 2 psi (13 kPa).
Once this procedure has been completed, release the air pressure by turning the needle valve counterclockwise. Disconnect the valve assembly and replace the modified plate with the standard cover plate.Ref: SENR6343 for 793,