Power steering tubing is blocked
Power steering fluid leaks – The first and most common reason to consider with respect to why you are not getting enough power from your power steering is you may have one or more leaks in your system. You constantly have fluid being forced through your power steering hoses at high pressure, so it is not at all surprising that one of those could at some point spring a leak. If this is your problem, you will need to replace your power steering fluid and find ways to stop the leaks from causing you to lose fluid in the future.
Power steering pump – Your power steering pumps are what force the power steering fluid through the system to create the hydraulic pressure you need. Even if you have enough power steering fluid in the system, if the pump isn’t working properly, you will not get adequate power steering. It’s hard to know if your problem is being caused by a fluid leak or a worn out pump, although some signs of pump problems are a humming or whining noise when you try to steer and the fact that your power steering fluid reservoir is relatively full even though you are not getting power steering. If this is your problem, you will need to replace the pump, so you want to exhaust all other possibilities before assuming that this is the source of your power steering issues.