VALVE GP-MAIN CONTROL 2851323 - Caterpillar

Service the air cleaner only with the engine stopped. Engine damage could result.
Illustration 1 g02793240
(1) Engine air filter service indicator
(2) Engine air filter service indicator reset button Inspect
The engine air filter service indicator is mounted in the compartment behind the cab on the left-hand side of the machine. Open the access door to inspect the indicator.
Use a towel to remove the dust which has collected on indicator (1).
Observe the performance of the air filter service indicator. The air filter element should be cleaned or the air filter element should be replaced when one of the following conditions occur:
The yellow diaphragm enters the red zone.
The red piston locks in the visible position.
If any component damage is present, replace the service indicator.
If air leaks are present, replace the service indicator. Test
Check for ease of resetting. Push up on button (2) to reset the service indicator. The service indicator should reset in less than three pushes.
Check the movement of the yellow core when the engine is accelerated to the engine rated speed. The yellow core should latch approximately at the greatest vacuum that is attained. If the service indicator does not reset easily, or if the yellow core does not latch at the greatest vacuum, the service indicator should be replaced. If the new service indicator will not reset, the hole for the service indicator may be plugged.Replace
Replace the service indicator if the following conditions exist:
The machine is used in a severely dusty environment.
The engine is overhauled.
Major components are replaced.Note: Replace the service indicator annually regardless of the operating conditions. Note: When a new service indicator is installed, excessive force may crack the top of the service indicator. Tighten the service indicator to a torque of 2 N m (18 lb in).