单项选择题
A.a defective or broken high pressure un-loader
B.a loose valve plate
C.excessive overload
D.no compression
单项选择题 Rotation of the steering wheel on the navigation bridge initiates oil pressure being applied to the steering gear rams by （）.
单项选择题 Which characteristic or condition will have the greatest effect on increasing a hydraulic oils viscosity?（）
单项选择题 When there is no movement of the rams on an electro-hydraulic steering gear, the tilting box of the running pump is （）.