MAINTENANCE D. HYDRAULIC SYSTEM INSPECTION AND MAINTENANCE OF HYDRAULIC EQUIPMENT CAUTION: During operation, the parts of the hydrau- lic system become very hot. Allow the machine to cool down before beginning in- spection or maintenance. 1. Be sure that the machine is parked on a level, firm surface before servicing hydraulic equipment. 2. Lower the bucket to the ground and stop the engine. 3. Begin servicing hydraulic components only after compo- nents, hydraulic oil and lubricants are completely cooled, and after releasing residual pressure. 3.1 Bleed air from the hydraulic oil tank to release internal pressure. 3.2 Allow the machine to cool down.
Note that servicing heated and pressurized hydraulic components may cause hot parts and/or oil to fly off or escape suddenly, possibly resulting in personal injury. 3.3 Keep body parts and face away from plugs or screws when removing them. Hydraulic components may be pressurized even when cooled. 3.4 Never attempt to service or inspect the travel and swing motor circuits on slopes. They are highly pressurized due to self-weight. 4. When connecting hydraulic hoses and pipes, take spe- cial care to keep seal surfaces free from dirt and to avoid damaging them. Keep these precautions in mind:
4.1 Wash hoses, pipes, and the tank interior with a washing liquid and thoroughly wipe it out before reconnecting them. 4.2 Only use O-rings that are free of damage or defects. Be careful not to damage them during reassembly. 4.3 Do not allow high pressure hoses to twist when con- necting them. The life of twisted hoses will be short- ened considerably. 4.4 Carefully tighten low pressure hose clamps. Do not overtighten them. 7-36