The steering system of passenger cars includes steering booster, power steering pump, oil sump, and connecting tubes.
Before the adoption of Bundy tubes, cold drawn steel tubes of Φ12×1 are used to connect the components. The allowable pressure of the fluid is 10MPa.
The higher volume of the inside surface residue must be eliminated by acid pickling. A while after the pickling, the insider surface would rust, and the rust chips could be carried by the working fluid to other components, especially steering pump. They fastens the wearing of the internal parts of the pump and worsens the steering performance, resulting the drop of the steering power and steering speed.
After the replacement of cold drawn tubes by Bundy tubes, the cleanness of the fluid is guaranteed by the high inner cleanness of Bundy tube, and thus improved the reliability of the system components.
Besides, the system safety level rises since the allowable working pressure of the fluid is raised to 12.8Mpa.