VALVE GP-CONTROL 3811520 - Caterpillar

Hydraulic oil pressure can remain in the hydraulic systems after the engine and pump have been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic systems. To prevent possible injury, refer to the section, Testing and Adjusting, "Hydraulic System Pressure - Release" before any fitting, hose or component is loosened, tightened, removed or adjusted.When possible, the bucket or attachment must always be lowered to the ground before service is started. When it is necessary for the boom to be in the raised position while tests or adjustments are done, be sure that the boom, stick and bucket or attachment have correct support.The swing lock (if equipped) must be engaged before service is started.Always move the machine to a location away from the travel of other machines. Be sure that other personnel are not near the machine when the engine is running and tests or adjustments are being made.
Disconnection
Illustration 1 g01074783
Quick Coupler Assembly (1) Male End (2) Safety Sleeve (3) Female End (4) Main Sleeve
Pull back the safety sleeve (2) .
Unscrew main sleeve (4) with the safety sleeve (2) in the back position.
Release the safety sleeve (2) and continue to unscrew the main sleeve (4) until the disconnection is achieved.Note: If the safety sleeve (2) will not unlock, turn the main sleeve (4) clockwise. This should allow the safety sleeve (2) to pull back.
After disconnection, clean the surface and connect the dust cap with the mating quick disconnect coupling in order to protect the couplings from dirt and other foreign material.Note: Always connect the dust cap to the connector ends when the quick disconnect coupling is not connected to the mating quick disconnect coupling. This keeps dirt and other foreign material from contaminating the hydraulic system.Connection
Illustration 2 g01075126
Quick Coupler Assembly (1) Male End (3) Female End (4) Main Sleeve
Remove the dust cap from the male quick disconnect coupling and the female quick disconnect coupling. Carefully clean all the mating surfaces of the quick disconnect coupling assembly.
Hold the flat face of the female end (3) of the coupler against the male end (1) of the coupler. Hold the female end (3) forward and rotate the main sleeve (4) of the coupler clockwise.
Illustration 3 g01074785
Quick Coupler Assembly (2) Safety Sleeve
Continue the manual connection if pressure is not felt. If pressure is detected use an open wrench and turn the coupler clockwise until the connection is completed. The completed connection is determined by the automatic feed of the safety sleeve (2). This prevents the incidental loosening of the hose due to vibration.
Connect the male cap and the female cap together.Note: Always connect the dust cap to another dust cap when the quick disconnect coupling is active. This keeps dirt and other foreign material from contaminating the hydraulic system.