1. Maintenance every 50 working hours(1) Tighten the connecting bolts of the front and rear transmission shafts.(2) Check the transmission oil level.(3) Check the oil level of the brake booster.(4) Check the tire pressure and damage.(5) Apply lubricating grease to the front and rear frame hinge points, transmission shafts, auxiliary frame pins, and other shafts under pressure.(6) Check the air filter element and replace it if necessary.