一台D85A-18推土机在使用中操作失灵，其操纵杆在浮动位置时推土机铲刀实现了浮动工况，铲刀反而徐徐下降，以致驾驶员在平整路面时很难控制铲刀。按照常现的先易后难的故障排除法，首先拆检了液压缸并更换油封，然后拆检并更换了操纵分配阀，仍解决不了问题，最后采用了断开操 A D85A-18 bulldozer malfunctioned in use. The bulldozer blade had a floating condition when the joystick was in the floating position, and the blade was gradually lowered, making it difficult for the driver to control the blade while leveling the road surface. According to the often-easier troubleshooting method, the hydraulic cylinder was first dismantled and the oil seal was replaced. Then the inspection and replacement valve was dismantled and replaced, and the problem could not be solved. Finally, the disconnection was adopted.