Part 1. Preparation and safety
Objective
- Safely pressure test a power steering system.
Personal safety
Whenever you perform a task in the workshop you must use personal protective clothing and equipment that is appropriate for the task and which conforms to your local safety regulations and policies. Among other items, this may include:
- Work clothing - such as coveralls and steel-capped footwear
- Eye protection - such as safety glasses and face masks
- Ear protection - such as earmuffs and earplugs
- Hand protection – such as rubber gloves and barrier cream
- Respiratory equipment – such as face masks and valved respirators
If you are not certain what is appropriate or required, ask your supervisor.
Safety check
- Be aware of moving drive belts and accessories when the engine is running.
- Power steering fluid can become very hot in operation. Take precautions to avoid burns.
- Power steering systems can reach a working pressure of over 1,000 pounds per square inch or 6,700Kpa during operation. Always follow manufacturers or equipment manufacturers procedure when working on the system.
- Power steering fluid is flammable. Always keep it away from hot exhaust manifolds, pipes, or catalytic converters.
- Clean up any spills immediately.
- Wear appropriate heat proof chemical gloves when the system is hot.
- Make sure that you understand and observe all legislative and personal safety procedures when carrying out the following tasks. If you are unsure of what these are, ask your supervisor.
Points to note
- Dispose of discarded fluid properly.
- Use only the specified power steering fluid for the vehicle.
- When the service is complete, check for leaks, check operation by turning the steering wheels to full lock in either direction and back to the center, and check the fluid level.
Part 2: Step-by-step instruction
- Prepare the vehicle
Safely raise the vehicle to make sure the front wheels are off the ground and locate the catch tray under the power steering system.
- Connect the pressure gauge
Following the manufacturers instructions for the pressure gauge/analyzer you are using, disconnect the high-pressure hose from the power steering pump. Connect the inlet hose from the gauge to the high-pressure connection on the power steering pump, using the appropriate adapter. Be careful not to loose too much fluid. Connect the high-pressure hose to the outlet valve on the pressure gauge using the appropriate adapter. With the pressure gauge control valve open, start the engine and run it at idle until fluid circulates through the tester and hoses, and the air is purged from the fluid. Turn the engine off. Check the power steering fluid level, and add fluid if necessary.
- Perform a pressure test
Start the engine again. Record the initial pressure and flow readings on the pressure gauge. Close and open the pressure gauge control valve, making sure the valve is not left closed for more than five seconds. Record the highest pressure indicated. Close and open the valve two more times, noting the high-pressure readings each time.
- Perform a flow test
With the pressure tester control valve open, turn the steering wheel to the extreme left. Record the highest indicated pressure at lock. Turn the steering wheel to the extreme right and record the pressure again. Turn off the engine. Compare these readings to the specifications in the vehicle service manual and take your findings to your supervisor.
- Disconnect the gauge
Disconnect the analyzer hose from the high-pressure connection point on the power steering pump and remove the adapter. Reconnect the vehicle’s power steering system high-pressure hose to the power steering pump outlet. Top up the power steering reservoir.
- Bleed the system
Lower the vehicle. Start the engine, and turn the steering wheel from lock to lock to check the system is working correctly with the vehicle load on the tires. Dispose of the waste power steering fluid in an environmentally approved way.
