Q: Power steering stiff sometimes and makes whining noise when turning

This may be related to a failing power steering pump or low power steering fluid levels. As you may know, the power steering system uses a pump, normally driven by a belt. The pump supplies pressure as it is turned by your engine, and driver control is supplied by either the rack and pinion or a steering gear box. Fluid pressure from the pump is used to push against a piston.

When the wheel is turned, pressure flows to one side and this piston moves. The piston is attached to the steering gears. As the hydraulic pressure does the work, the driver controls the direction by turning the steering wheel. The operation of this is accomplished with a very sensitive valve system called a rack and pinion. The rack and pinion gear set does two things:

• It converts the rotational motion of the steering wheel into the linear motion needed to turn the wheels.

• Secondly, it also provides a gear reduction, making it easier to turn the wheels by the use of reduction gears where the steering shaft connects.

This system uses a torsion bar driven valve to direct and relieve pressure in a cylinder. When the steering wheel is not being turned, the steering valve is at rest. In this position fluid flows around the valve and out to the reservoir which is where the power steering fluid resides when not at work. Slight pressure also enters both sides of the assist cylinder. Because pressure is equal on both sides of the piston nothing occurs when the wheel is straight ad no assistance is need to turn the wheels either way.

To avoid unnecessary repairs, consider YourMechanic, as one of our qualified technicians can come to your home or office to diagnose the issue with your steering and help you make an accurate repair.