CONTROL GP-SERVICE BRAKE 8Y7623 - Caterpillar

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).
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 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, "Caterpillar Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Caterpillar products.Dispose of all fluids according to local regulations and mandates.
Before any tests are performed, visually inspect the complete hydraulic system for oil leaks and damaged parts. Refer to Testing and Adjusting, "Visual Inspection". Before any tests are performed, prepare the machine for troubleshooting. Refer to Testing and Adjusting, "Machine Preparation for Troubleshooting".
Move the machine to a smooth, horizontal location. Move the machine away from other operating machines and away from personnel.
Lower the loader bucket to the ground. Stop the engine.
Engage the parking brake.
Place chocks in front of the wheels and behind the wheels.
Turn the engine start switch key to the ON position.
Move the control levers to all positions in order to release the pressure in the hydraulic system.
Turn the engine start switch key to the OFF position.
Illustration 1 g01804516
(A) Location of the Accumulator
Illustration 2 g00557001
Accumulator (1) Screws. (2) Valve. (3) Valve cap. (4) Protector.
Remove one screw (1) and rotate the protector (4). Remove valve cap (3) .
Illustration 3 g00509122
Group for nitrogen charging (5) Pressure gauge. (6) Valve. (7) Pressure gauge. (8) Regulator assembly. (9) Pressure regulating screw. (10) Nipple assembly for the nitrogen cylinder valve. (11) Valve handle. (12) Chuck.
Turn the valve (6) completely in the clockwise direction. Turn the valve handle (11) completely in the counterclockwise direction.
Install the chuck (12) to the valve (2) .
Turn the valve handle (11) completely in the clockwise direction. The reading on the pressure gauge (7) should be 1860 34.5 kPa (270 5.0 psi).
If the reading on the pressure gauge is too high, repeat steps 5 through 7. This ensures that there is no hydraulic oil