The job of replacing a power Steering Pump is relatively easy for a competent mechanic and involves several distinct stages which will help you to ask the right questions when you book the work in a garage.
Draining the Old Fluid
First of all, the old fluid has to be drained from the reservoir. This is done with a pump or a big syringe to get all the old stuff out. After that, the mechanic has to dispose of it in an environmentally friendly way. The old fluid is dark and full of contaminants, so it is not good to mix it with the new stuff. Also, it is good to get rid of it so that it does not spill during the work and make a big mess.
Removing the Old Pump
The Steering Pump is usually belt driven on petrol and diesel vehicles. It is often part of a number of other accessories such as alternator, air conditioning, and water pump, driven by a serpentine belt. To remove the pump, the drive belt needs to be removed. This may also involve the removal of a pulley attached to the end of the pump shaft. Also, the high-pressure and low-pressure hoses need to be disconnected from the pump, and the pump mounting bracket unscrewed from the engine. A drip tray is placed under the pump to catch any residual fluid.
Fitting the Replacement Unit
A new or reconditioned power steering pump is then bolted to the same location. It must be correctly torqued in accordance with the manufacturer’s instructions. Also new sealing washers must be fitted to the hose unions, as the old ones may be OK to look at but start to weep. The drive belt or serpentine belt is then refitted. It must be correctly tensioned; if it is too slack then it will cause noise and reduce the performance of the power steering pump.
Refilling With the Correct Fluid
When filling a vehicle with Power Steering Fluid it is VERY important that the correct type is used. The fluid type for a Power Steering System can vary from one vehicle to another. Some vehicles use ATF (Automatic Transmission Fluid) while others use a dedicated Power Steering Fluid. Using the wrong type of fluid can cause seal damage over time.
Bleeding the System
Air in the power steering system can cause the car to pull to one side and give a ‘notchy’ feel when turning at low speed. Air enters the system when the pump is opened up for refilling. With the engine running slowly, turn and shut the steering lock several times. This will allow the fluid to run through the pump and release any air that has entered the system. Once the air has been removed, check the level of fluid in the reservoir and top up as required.
Final Checks and Road Test
A final check is made for any signs of leakage around the various hose connections. Also checked is the belt for any signs of slippage. Finally a road test is undertaken to check for any pulling to one side or other signs of problem, such as unusual noise when turned fully to lock. Pulling to one side can be due to a hose which contains air. Drips from any of the various joints can be due to over tightening of the joints and requires re-tightening.
The replacement should not leak, the belt should be correctly tensioned and the car should steer smoothly as if it was new when hot or cold.
