HARNESS AS 8W0996 - Caterpillar

DOUBLE CHECK VALVE
1. Inlet passage from scraper governor control valve. 2. Shuttle. 3. Inlet passage from throttle lock control valve. 4. Outlet passage to scraper engine air chamber.Air Chamber For The Tractor/Scraper Engine Governor
LOCATION OF AIR CHAMBER FOR THROTTLE LOCK ON THE TRACTOR ENGINE GOVERNOR
LOCATION OF AIR CHAMBER FOR THROTTLE LOCK ON THE SCRAPER ENGINE GOVERNORThe air chamber that controls the scraper engine governor is fastened directly to the scraper engine. Rod assembly (3) is connected through a rod end to the lever on the governor. Pressure air from the scraper governor control valve on the tractor goes through inlet passage (1) to the top of diaphragm (2). The pressure air moves the diaphragm and rod assembly (3) against the force of spring (4). As the rod assembly moves out of the air chamber, the lever on the governor moves to the HIGH IDLE position.When pressure air is released through the scraper governor control valve, spring (4) will move the rod assembly back into the air chamber. The governor lever will move to the LOW IDLE position. The amount of pressure air from the scraper governor control valve to the inlet passage of the air chamber controls the governor lever by the position of the rod assembly.
AIR CHAMBER
1. Inlet passage. 2. Diaphragm. 3. Rod assembly. 4. Spring.Button Control
LOCATION OF BUTTON CONTROL The air pressure must be above 520 kPa (75 psi) before the throttle lock will operate.The tractor and scraper engines can be held (locked) in HIGH IDLE position with throttle lock button (1). When the button is pushed in, the throttle lock control valve [connected to button (1)] sends air pressure to throttle lock air chamber (2) and also to the scraper engine air chamber. Both air chambers move their respective engine governors to HIGH IDLE position.The air chambers on the tractor and scraper operate the same. The air chamber is connected to the mechanical linkage of the tractor engine governor control. When the air chamber is activated, it moves the linkage and pedal for the tractor engine governor.When throttle lock button is pulled out or the the brake pedal is pushed, the throttle lock control valve stops the flow of pressure air to the air chambers. The tractor and scrapers engines now go back to low idle position.Throttle Lock Control Valve
THROTTLE LOCK CONTROL VALVE
1. Plunger. 2. Spring. 3. Supply passage. 4. Orifice. 5. Delivery passage. 6. Valve. 7. Exhaust passage. 8. Valve seat. 9. Piston. 10. Pilot passage.The throttle lock button is fastened to plunger (1). Valve (6) is fastened to the plunger. Spring (2) holds the valve and plunger in the up (exhaust) position. In this position, pressure air in supply passage (3) is not permitted to go to delivery passage (5) and activate the air chambers for throttle lock operation.When the throttle lock button is pushed in, plunger (1) and valve (6) are pushed down until valve (6) comes in contact with valve seat (8). Pressure air from supply passage (3) is now free