HORN GP-AIR 6G5290 - Caterpillar

Sudden movement of the machine or the release of oil under pressure can cause personal injury. At operating temperature, the hydraulic oil is hot and under pressure. Hot oil can cause burns. To prevent possible personal injury, release the pressure in all of the implement circuits before any hydraulic lines or components are disconnected or removed.
1. Release the pressure in the hydraulic system as follows:a. Move the machine to a smooth horizontal location. Move away from working machines and personnel.b. Permit only one operator on the machine. Keep all other personnel either away from the machine or in view of the operator.c. Move the switch for the CUSHION-HITCH to the "LOCKDOWN" position. Be sure the rear bracket assembly of the hitch is down against (resting on) the front hitch assembly.d. Activate the parking and secondary brakes. Lower the bowl to the ground. Lower the apron. Stop the engine.e. Move all scraper control levers to all positions to release the pressure in the hydraulic system.f. Carefully loosen the fill cap on the hydraulic oil tank to release the pressure in the tank.g. Be sure all hydraulic pressure is released before any fittings, hoses or components are loosened, tightened, removed or adjusted. Wait at least five minutes after the machine is turned off. 2. Put identification marks on three hose assemblies (1) for installation purposes. Disconnect the three hose assemblies from the elevator control valve. Put plugs in the hose assemblies to keep dirt out of the hydraulic system.3. Remove six Allen head bolts (2). Remove elevator control valve (3). Remove the two O-ring seals from the elevator control valve. The following steps are for the installation of the elevator control valve.4. Check the condition of the two O-ring seals used in the elevator control valve and in the ends of hose assemblies (1).