How a steering System Works
A Typical car Steering rack
There are basically two styles of vehicle steering systems, rack and pinion and worm gear box. Rack and pinion steering is one of the oldest types of steering systems and is still used today. Inside the rack body a flat rack gear moves in a linear direction driven by a circular gear called a pinion. The steering wheel is connected to the pinion gear (shaft).
Rack and Pinion Steering
The rack gear is connected to an inner tie rod end that is covered by a rubber bellow. The inner tie rod end is connected to the outer tie rod end. These rod ends have the ability to move in any linear direction. Finally, the tie rod end is connected to the wheel spindle.
A worm gear box style of steering system is constructed of two main parts much like the rack and pinion style system. The main part is called a worm gear; the other is a selector shaft gear. The worm gear is connected to the pitman arm and then to a center link and tie rod ends. The opposing end of the center link is supported by an idler arm, which is located on the opposite side of the frame from the steering box.
Car Steering Box worm gear
Steering can be either power or manual Power steering. utilizes a hydraulic pump mounted on the engine, and driven with a serpentine belt. The fluid in the system is held under pressure until the wheel is turned which releases the pressure and applies it to the steering system. The power steering system fluid should be checked at every service interval. Fluid leaks are a common problem on power steering systems. When a leak is detected inspect the system to determine the course of action, then remove damaged or worn parts and reassemble. Refill system with approved fluid for you particular vehicle. When the power steering system is low a groaning noise will be heard when the vehicle steering is activated. This is caused by the power steering pump scavenging for fluid and taking in air.
When the enginge is off or the system has run completely out of fluid it will be very difficult to steer the vehicle. It is advised not to move a vehicle with power steering when either of these conditions exists. Any steering component malfunction can cause the vehicle to be uncontrollable. All steering components should be inspected for "play" at regular intervals and replaced as needed. When steering components are replaced an alignment is required. Power steering system maintenance is required periodically according to the manufacturer's instructions for your vehicle Most manufacturers recommend having the hydraulic fluid in the power steering system changed every 60,000 miles.
Power steering FLUSHING procedure
Once a rack & pinion has been removed from a vehicle, the power steering pump and lines must be flushed to remove all the old fluid. Skipping this important step can cause the rack to fail and void your warranty and will shorten the life of the replacement rack & pinion by circulating all the contaminants from the dirty fluid right back into the new rack.
- A clean system is a must.
- Flushing [follow owner’s manual and instructions] can be accomplished by raising the front wheels off the ground and pouring fresh fluid through the pump reservoir allowing the fluid to drain out the return line. When the rack is back in the chassis, reconnect only the return line to the rack. Place the pressure line from the pump in a drain pan. Fill the pump reservoir with the [specified by the vehicle manufacturer] correct type of power steering fluid, then crank the engine over or turn the pump by hand. Add two quarts of new PS fluid to the pump reservoir, and then reconnect the pressure line to the pump.
- When installing the pressure lines on the rack, extreme care must be taken not to overtighten the fittings. Some lines are designed to swivel after they have been tightened to provide flexibility during installation and to accommodate engine vibration. Overtightening the line fittings can strip the soft aluminum threads in the rack and damage housing.
- After filling the system, you will have to bleed the system to remove trapped air. One recommended method is done my raising the front wheels off the ground, then slowly turning the steering from side to side at least five times with the engine off until no more bubbles can be seen in the fluid reservoir, and the reservoir level remains steady.
- Then, disable the ignition and crank the engine over several times while observing the fluid in the pump reservoir. Make sure the fluid reservoir is full when you have finished.