There’s an easy way to tell: the tiny particles worn off the seals darkens the colour of the power steering fluid. Compare the colour to a new power steering fluid – if it is noticeably darker, you should to replace it.
Many drivers may not remember the days before power steering – we couldn’t turn a corner one handed. Now, we can turn the wheel with one finger, all thanks to hydraulic power steering fluid. The power steering fluid travels from a reservoir to a pump where it is pressurized and pushed to either a steering rack or box where the pressurized fluid helps perform the mechanical work of steering, as directed by the driver.
To make the power steering system work, the power steering fluid must be sealed in and moved around. To seal in moving parts you need special types of rubber seals. Ideally this system would never leak or degrade and never require a power steering service. Unfortunately, as the seals on the various moving parts work against their mating surfaces, they wear slightly, leaving tiny particles in the fluid. Also, the fluid tends to become oxidized because of exposure to the atmosphere through tiny leaks and continuous heating and cooling.
Power steering needs to be changed or flushed periodically. This provides an opportunity to remove the oxidized fluid which contains the fine, abrasive particles shed from seals and replace it with new fluid. Some new fluids also have properties than aid in maintaining seals’ pliability and sealing properties. Because of the obvious importance of the vehicles steering system, it is important that the system receive regular inspection and maintenance from a certified professional technician.
A power steering maintenance service reduces wear and tear and reduces risk of total system failure. Delaying the power steering service a short while will not likely cause immediate failure, but additional wear and tear is additional risk. Ultimately it is your choice to balance risk vs budget.
Oxidized and dirty fluid will cause power steering components to wear out faster. The power steering pump, which provides pressure to turn the wheels will eventually fail; if you are driving the loss of power steering could make controlling your vehicle difficult. You would have to get a mechanic to replace the power steering pump. Subsequently, other power steering components may wear out.