SPACER 1919387 - Caterpillar

Personal injury can result from hydraulic oil pressure and hot oil.Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system.Make sure all of the attachments have been lowered, oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand.
Dry nitrogen is the only gas approved for use in the accumulators. The charging of oxygen gas in an accumulator will cause an explosion. An explosion can be eliminated by using nitrogen gas cylinders with standard CGA (Compressed Gas Association, Inc.) No. 580 connectors. When nitrogen gas is ordered, make sure to order the cylinders with CGA No. 580 connectors.Do not rely on color codes or other methods of identification to tell the difference between nitrogen and oxygen cylinders. In any application, never use an adapter to connect your nitrogen charging group to a valve outlet used on both nitrogen, oxygen, or other gas cylinders. BE SURE YOU USE DRY NITROGEN (99.8% purity).
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids.Refer to Special Publication, NENG2500, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat® products.Dispose of all fluids according to local regulations and mandates.
Specifications
Table 1
Brake Accumulator Cut-in / Cutout Pressure
Brake Accumulator Precharge Pressure 5515 275 kPa (800 40 psi)
Cut-in Pressure 11700 900 kPa (1697 131 psi)
Cutout Pressure 17200 900 kPa (2495 131 psi) Machine Preparation
Prepare the machine for testing by completing the procedure that is specified in the Service Manual module Testing and Adjusting, "Machine Preparation for Troubleshooting" for the machine that is being serviced.Testing the Brake Accumulators
This test checks the following components: the cut-in pressure, the cutout pressure, nitrogen precharge and the pressure switch that indicates low oil pressure.
Table 2
REQUIRED TOOLS
Part Number Description Quantity
"JEBD3003" Caterpillar Electronic Technician (ET) 1
171-4400 Communication Adapter Tool 1
Stop the engine. Engage the parking brake. Depress the brake pedal repeatedly until there is no brake oil pressure. Pause for 2 seconds between each of the applications.
Connect the Communication Adapter Tool to a laptop computer that is equipped with Caterpillar Electronic Technician (ET). Connect the Communication Adapter Tool to the data link connector. Note: The brake system pressure must be monitored with ET.
Observe the pressure. Before you start the engine, the oil pressure should be 0 kPa (0 psi).
Start the engine. The oil pressure will increase to a maximum. Record this pressure. This value is the cutout pressure of the charging system for the brake accumulators.
Apply the service brakes repeatedly while the engine is running. Verify that the pressure drops consistently.