STEM AS-BUCKET 3527055 - Caterpillar

When possible, the bucket 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 have correct support.The swing lock 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.Release Of Pressure In The Hydraulic System
Release the pressure in the implement hydraulic circuits (boom, stick and bucket) before any hydraulic lines or components are disconnected or removed.1. Fully retract the rod in the stick cylinder.2. Adjust the position of the bucket so that it is flat on the ground.3. Lower the boom until the bucket is flat on the ground.4. Shut off the engine and put the hydraulic activation control lever in the UNLOCK position.5. Move the control levers for boom, bucket, stick and swing to all FULL STROKE positions. This relieves any pressure that might be present in the pilot system.6. Slowly loosen the air vent plug on the hydraulic tank and release the pressure.7. Tighten the air vent plug on the hydraulic tank.8. The pressure in the system should now be released and lines and components can be removed. The boom cylinder lines may still be pressurized if equipped with boom lowering check attachment. There are bleed valves at the boom cylinders that can be opened to relieve any oil pressure that may remain.Visual Checks
A visual inspection of the system is the first step when troubleshooting a problem. Make this inspection with the engine OFF and the implements lowered to the ground.1. Check the level of the oil in the hydraulic tank. Slowly loosen the tank filler cap and release the pressure before the cap is removed.2. Remove hydraulic filter elements and check for material that would give an indication of damage to a component.3. Inspect all lines and connections for damage or leaks.4. Inspect control linkage for bent, broken or damaged components.Checks During Operation
Checks during operation can be used to find leakage in the system. They can also be used to find a valve or pump that is not working correctly. The speed of cylinder rod movement or the torque on a motor can be used to check the condition of the cylinders, motors and pumps.Raise or lower the boom. Move the stick in and out. Open and close the bucket. Swing the machine to the right and left. Do each of these operations several times and consider the following items:1. Pilot System: The pilot system controls the movement of the spools in the main control valve. It is important that the pressure and flow from the pilot pump be according to specifications. A problem in the pilot system usually affects many or all of the machine functions. 2. Signal Relief: The signal relief valve controls