HT25 - MAINTENANCE 87 To relieve digging chain tension, stand on opposite side of boom and unscrew check valve zerk (1) to release grease. NOTICE: Do not overtension chain. Premature chain failure could result. Fluid pressure could pierce skin and cause injury or death. Stay away. NOTICE: Service digging boom grease cylinder only while standing on opposite side of boom. Wear gloves and safety glasses and cover fitting with cloth when relieving pressure in cylinder. Adjust digging chain tension every 10 hours. With boom horizontal, pull up on chain until it is taut. Measure distance (2) from top of boom to chain. Correct distance is 1.5 to 2 in (40 to 50 mm).
To tighten chain, pump MPG into cylinder at check valve zerk (1). p Chain Tension TRENCHER