PISTON GROUP 7N3636 - Caterpillar

Personal injury can result if the machine moves while testing.If the machine begins to move during test, reduce the engine speed immediately and engage the parking brake.
Sudden movement of the machine or release of oil under pressure can cause injury to persons on or near the machine.To prevent possible injury, perform the procedure that follows before testing and adjusting the brake system.
Personal injury or death can result from escaping fluid under pressure.Escaping fluid under pressure, even a very small pin-hole size leak, can penetrate body tissue and cause serious injury and possible death. If fluid is injected into your skin, it must be treated immediately by a doctor familiar with this type of injury.Always use a board or cardboard when checking for a leak.
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.Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide"for tools and supplies to collect and contain fluids in Caterpillar machines.Dispose of all fluids according to local regulations.
Specifications
Table 1
Brake Accumulator Charging Valve - Test
Date Equipment ID Code
Description Specification Actual
Cut-in Pressure 14700 kPa (2130 psi)
Cut-out Pressure 19800 kPa (2870 psi) Introduction
The following test includes all the required information needed to perform a test and adjust procedure on the brake accumulator charging valve.Test Preparation
Move the machine to a smooth horizontal location. Move away from any machines that are working and any personnel.
Move the transmission control to the P position.
Move the engine start switch to the OFF position to stop the engine.Note: Moving the engine start switch to the OFF will also release the hydraulic brake pressure from the brake accumulators.
Permit only one operator on the machine. Either keep other personnel away from the machine, or keep other personnel in the sight of the operator.
Place blocks in front of the wheels and behind the wheels.Test Procedure
Illustration 1 g06199619
The arrows indicate the location of the factory installed pressure sensors for constantly monitoring the brake accumulator pressure. The accumulators are located on the left side of the machine next to the rear tires.
Use Cat® Electronic Technician (Cat® ET)or the operator monitor screen to observe the accumulator pressure.
Start the engine. Allow enough time for the brake accumulators to charge completely.
Run the engine at low idle.Note: The pressure in the brake accumulators will slowly decrease due to leakage in the brake system.Allow the accumulators to cycle at least ten times before any measurement is made.Note: Pressure decreasing from cut-out to cut-in and then rising back to cut-out is one cycle
Observe the cut-in pressure and the cut-out pressure. Record the pressures in Table 1.Note: The cut-in pressure and the cut-out pressure should be verified through Cat ET.
After recording the pressures, stop the engine and remove the test equipment.
If the cut-in pressure and the cut-out pressure are out of specification, refer to the "Adjustment Procedure" Section.Adjustment Procedure
Illustration 2 g06221806
View of the two