Symptom: There is a B4 Passat sedan turned to the pump ring, the direction of the pendulum, the starting car has "whining" sound, playing the steering wheel sound increased.
    Troubleshooting: B4 Passat used in the steering pump is driven by the engine rotor impeller pump, when not turn, turn the distribution valve to keep open, steering the cylinder on both sides of the working chamber and low pressure back to the tubing does not work, turn the impeller The oil output from the pump flows back to the tank by the steering valve. Due to steering pressure and flow limit valve throttle resistance is very small, so the impeller pump output pressure is very low, turn the bow after the positive, the impeller pump is actually in idle state.
    When turned, the corresponding working chamber in the steering cylinder is disconnected from the oil return line and is connected to the output line of the impeller pump, and the other chamber in the booster cylinder is still passed back to the oil return line, Flow resistance is much higher impeller pump output pipe resistance, which through the impeller pump, with a certain pressure of the fluid, the distribution valve to promote the piston driven by the role of the rack.
    From the above mechanism is not difficult to see that the steering wheel is put, the starting car has "whining" sound, when the direction of the increase, and can be sure that the higher the engine speed, the greater the sound, steering wheel angle, the more powerful The The reasons for this phenomenon, mainly in the following areas:
    ① return pipe or diverter blocked, oil pressure is too high.
    ② steering pump bearing damage.
    ③ The oil pan or rotor is damaged.
    ④ stator wear excessive.
    ⑤ pressure and flow control valve problems.
    As for how long the pump can be maintained, it should be carefully checked for this pump to determine which cause the pump is causing the pump. In the case of tubing or other components and steering gears, other components should be removed without having to replace the steering pump. If the bearing is abnormal, stator wear or rotor damage should be replaced promptly. If necessary, through the pressure test, then meter measurement, basically able to determine the degree of damage within the pump, the car up, in the car to hear or feel the load to increase the sound, and pressure in the standard range, Still can run a long distance should be no problem, the pressure standard is 7.2-8.4MPa (90-105Bar), if the pressure is low, the direction of the sink should be replaced or repaired in time to avoid damage to the steering or other parts, it is important to ensure traffic safety The