Power steering is found on most modern vehicles these days and is no longer reserved only for the flagship models as was the case in the past. Manual steering systems are still found on some entry level vehicles but power steering is definately becoming the norm. Since this is the case, I will focus on power steering systems.
The most common types of units are the power steering box, which is used mainly on vehicles with heavy duty applications such as pick up trucks, 4x4's and lorries and has largely disappeared from cars altogether, and the power steering rack which is used in all cars but is found more and more on 4x4 vehicles and pick up trucks in a more heavy duty version than is found in cars. Electric power steering systems are finding their way into the market place and is a new technology. There are pro's and con's to hydraulic power steering, electric power steering and hybrid power steering systems.
It is imperative that one keeps their power steering system operating correctly so as to avoid costly repairs. The system is closed in most cases (power steering fluid is used only for the power steering application) except for a minority of vehicles that have hydraulic cooling fans or hydrobooster applications for brakes. Fluid levels must be monitored regularly so as to be aware of any loss of fluid in the system.Generally, the fluid used is of a red colour that meets Dexron II or III ATF specifications but there are also other types of fluids around which are mineral based and are green or yellow in colour. Consult your vehicle's manual in order to determine which fluid should be used in your system.
Seals
Since rubber seals, o-rings and pipes have a finite life, they become brittle and lose their elasticity over time due to the pressure and heat they are subjected to. If the fluid level is low, the system probably has a leak. Inspect the entire system to determine where the fluid is going to. Leaks can occur at the power steering pump, the power steering input shaft to which the steering coupling is connected, from the seals inside the power steering rack itself or from the power steering box sector shaft, or from the hoses.
Power steering rack
By squeezing the power steering rack boots on the ends of the steering rack, one is able to check for fluid that has leaked past the seals internally. If you can feel fluid inside the power steering rack boots, the steering rack needs to be overhauled. Another reason for the steering rack to leak is that there is a presence of moisture inside the boots probably from a torn boot. This will corrode the shaft and cause the steering shaft to tear the seals. If the colour of the power steering fluid is purple and the power steering rack is an aluminium one, it is a sign that that the power steering fluid is very old and contaminated and should be replaced.
Power steering box
Since there are no boots on a power steering box, it is easier to detect leaks. Usually, these are found at the power steering input shaft or the main sector shaft seal. Corrosion of the shaft is also a culprit in many cases especially if the vehicle is 4x4 and does a lot of offroad work. Another reason for the power steering box to start leaking could be as a result of a collapsed bearing. This is dangerous and must be attended to immediately.
Power steering pump
The power steering pump can be thought of as the heart of the the system - much like the human heart. It is responsible for supplying flow and pressure to the entire power steering system. If the all the power steering fluid is allowed to leak out the system, the power steering pump will run dry and irreversible damage can take place. The noise associated with this is a loud growl. This needs to be attended to immediately. On some vehicles, the power steering pump is run on an independant belt (does not rely on one belt to run the airconditioner, alternator and power steering pump). In this case the belt may be removed temporarily in order to save your pump until it can be attended to. Bear in mind that if the belt is removed, the power steering will not function until such time the belt is refitted. A squealing sound is indicative of a slipping belt. Deglaze the pulley and replace the belt ensuring correct tension. If the squealing is as a result of oil leaking from the power steering pump, the pump needs to be overhauled.
Loose steering
Since vehicles spend most of their lives driving in the straight ahead position, it stands to reason that the power steering rack or power steering box in that position the will wear the most. This is felt by the steering wheel having a loose feeling and the vehicle wandering across the road. The driver needs to keep correcting the vehicle in order to keep it driving straight ahead. Many people simply tighten the adjustment thinking this wil remedy the problem. This may work in some cases, but sadly in many cases, this actually causes accelerated wear and can be dangerous and expensive if the person adjusting the power steering box or power steering rack does not fully understand the implication of this action.
Another cause for this is a worn tie rod end or ball joint, bush or other worn or broken suspension part. Seizing of these parts can also cause hard steering.
Remember, these parts are "LIFE and LIMB" parts. Let a professional attend to any faults you might suspect or contact me and I will be happy to assist.
© 2008 Powerbrake and Steering |
