If air gets into your car's power steering lines, it can have a negative impact on your ability to control the vehicle. When you lose power steering, it becomes difficult to turn the wheel. The only way to fix the problem is to bleed the lines to remove the air. This can be a simple process that takes a few seconds, but it may require a bit more attention and time.
Diagnosing air in the lines
When air gets in the line, it detracts from the pressure needed to keep things moving fluidly. This can cause whining noises to emanate from under the hood when you try to make a turn. You may also find it takes additional effort to turn the steering wheel. When you notice these issues, you should pop open the hood and get started determining if there's air in the lines. First, check the fluid level. If it's low, you could be dealing with a leak. When liquid can escape, air can find its way into the lines.
Turning the wheel a few times can also help you determine whether or not there's air in the system. The motion will churn up the fluid, and if there's air in it, you will likely find the power steering fluid looks a bit foamy.
Getting the air out
Often times, simply turning the wheel as far as it will go in both directions, or lock-to-lock, is enough to rid the system of air. However, this may not get the job done, in which case you may need to take more extreme measures and bleed the system manually. This basically involves flushing the fluid to force the air out. If you're handy in the garage, you may be able to perform this task yourself, but since it involves a moderate amount of precision you should defer to a professional if you're uncertain of whether you can tackle the project.
Bleeding the lines
The power steering system should have a bleeder valve designed specifically with this job in mind. Before you begin, you'll need power steering fluid, a funnel, a drainage container, a small hose or tubing and protective gloves and goggles. First, remove the power steering reservoir cap and top off the fluid. Then replace the cap and locate the valve - the owner's manual can help point you in the right direction. Attach the tubing to the valve and run it to the bucket or drain pan. You're now ready to begin bleeding the system.
Start the engine and loosen the valve a little bit. Then, return to the driver's seat and turn the wheel lock-to-lock. Turn the car off, close the valve and repeat the entire process, starting with topping off the fluid reservoir. Continue doing so until there are no air bubbles in the drain pan. At this point, you have successfully bled the system and your car's power steering should behave normally. If the issue crops up again shortly after this procedure, you're probably looking at a leak somewhere in the power steering system.
Until this issue is fixed, you're likely going to continue having trouble with the power steering. It is best to address the problem as soon as possible to save yourself the aggravation of losing steering. This can also help reduce your risk of losing control of your vehicle and crashing, which will probably leave you with more extensive repairs that will cost a lot more to fix than air in the power steering lines.