The power steering system in a vehicle is what enables the driver to turn the wheel easily. The system is made up of various components, which all combine to provide the hydraulic pressure that is necessary for its operation. These parts include belts, hoses, a power steering reservoir, a power steering pump, steering gear (either rack and pinion or a power steering box) and hydraulic fluid. The steering gear connects the steering wheel to the stub axles and when the steering wheel is turned with the engine running the pump sends hydraulic fluid to the steering gear, which applies the pressure required to turn the wheels.

Because the entire system depends on hydraulic pressure, one of its most important components is the power steering reservoir, where the hydraulic fluid is stored. If the power steering reservoir leaks or the fluid level becomes low, steering the car will become more difficult because there will be insufficient pressure to operate the system.

Signs that there may be a leak in the power steering reservoir include evidence of hydraulic fluid beneath the car, greater difficulty in steering and a groaning sound when the steering wheel is turned. If any of these indicators become evident, the power steering system should be inspected to ascertain whether the problem lies in a leak in the power steering reservoir or elsewhere in the system.