What Causes Power Steering to Be Hard in One Direction?

Power Steering Gear

The power steering gearbox gets the lion’s share of blame when a car or truck does not steer correctly. The steering gear box consists of a complex network of gears, hoses, cylinders, valves and a pump. It wields immense power and great care is required when working on the mechanism. Power steering enables the driver to steer the vehicle with minimal effort. Power steering is particularly helpful when the vehicle is traveling slowly or stopped. The power steering feature is usually a reliable mechanical component. Unless the vehicle is older or poorly maintained, the power steering feature should last the lifetime of the vehicle.

One Direction Problems

Difficult steering in one direction could point to a faulty valve in the steering gear mechanism. A malfunctioning valve will cause the steering gear fluid pressure to drop below manufacturer’s specifications. Poor fluid pressure may also be the result of a bad pump or a leaky hose, which affects fluid delivery. Poor fluid delivery will also cause the power steering to behave erratically. Other causes of hard steering in one direction is the vehicle’s front end binding due to faulty kingpins or steering linkages, air trapped in the hoses or fluid contamination.

Other Causes

A more likely scenario to hard steering in one direction is not the power steering gear, but low or unequal tire pressure or vehicle overload. Also unrelated to the gearbox is an improper front-end alignment. Instead of a broken component, such as a valve, pump or gear, the cause is more likely a hydraulic system that is performing poorly due to a leak because a seal is old or cracked. A hose also may be brittle due to age. Another common problem is a lose pump drive belt that requires tightening or replacement. Often shade tree mechanics fail to fill the fluid reservoir properly or use the wrong fluid, which will fail to properly lubricate the internal components.

Related Problems

Although a vehicle may be hard to steer in one direction, other problems could accompany the problem. The vehicle may shimmy or wander on the road. In addition, the steering wheel may not recover to its proper position once the driver completes a turn. These issues are usually created by low or unequal tire pressures. Worn or poorly lubricated wheel bearings, steering gear mounted loosely on the frame or even a loose wheel could also cause these issues.

Diagnosis

A vehicle owner should first check to make sure the tires are properly inflated and there are no leaks from the power steering gearbox or the hoses feeding into the box. At the steering box, examine the pump and steering mechanism, which will either be a rack and pinion or recirculating ball-type system. The discovery of a leak during this inspection is the most likely cause of hard steering. Another telltale sign is a whining noise coming from the box.