Avoid problems when repairing the power steering

Replacing a defective rack and pinion or power steering pump is often a time-consuming and expensive repair. Therefore, it is particularly annoying if the power steering is broken again shortly after, especially if it turns out that this could have been avoided. Too often, cleaning the hydraulic system is forgotten when a new power steering pump or rack and pinion is installed. Thereby, the lifespan of the new spare part and the other components of the servo system is reduced greatly.
The contamination of the servo system is unavoidable. Over time, small amounts of particles - such as small plastic, rubber and metal parts - find their way into the hydraulic oil. 

Contaminated hydraulic oil seen through a microscope
"In many cases, the pollution is so pronounced that the filter in the oil tank is completely blocked, I have seen many examples of this. Often the filter is not cleaned or replaced because the mechanic is unaware that there is a filter. A compromised filter hinders the pump’s oil supply and the pump will begin to cavitate - generate air bubbles, "says Troel Madsen, Product Coordinator at Triscan, continuing:" The problem with contamination is that it will cause wear and tear on e.g. packs, which over time become leaky. Therefore, it is important to always clean the entire hydraulic system when replacing a defective component".

Our Product coordinator Troels Madsen 

1. Drain existing fluid
2. Clean/replace filter
3. Clean the system for old liquid residues and other contaminants - if necessary, use a cleaning fluid/additive*
4. Install the new pump/rack and pinion
5. Fill in the new liquid
* (This can be done with a machine designed for this purpose)
The above procedure is recommended in cases where the impurities are limited. If a rack and pinion or a power steering pump has been severly damaged, another - and more comprehensive - approach is required, which can be found here.
By cleaning the servo system, the optimal conditions for a long life and optimum operating conditions of the new servo pump or rack and pinion are given.
A leaking rack and pinion boot can be expensive
When referring to contamination of the servo system, usually, the contaminant described at the beginning of this article is ment. However, pollution can also come from outside. A defective rack and pinion boot has two negative effects: Firstly, it allows the ingress of dirt in the seals of the steering parts. Secondly, it leads to the ingress of water with subsequent corrosion, ultimately leading to a leaky and defective rack and pinion. Always check the rack and pinion boot and replace it if necessary. Whether you choose a vehicle-specific or universal boot is not important. What is crucial is that the boot is tight.
Vehicle-specific rack and pinion boot (Triscan No.: 8500 10021) - fits Ford S-Max and Galaxy
Duraboot Universal rack and pinion boot (Triscan No.: 8500 210)

Alternatives for the mechanical-hydraulic servo system
With the desire to simplify service and reparations, to save space and to reduce the fuel consumption of cars, various alternatives for the mechanical-hydraulic servo system have been developed in recent decades.
On some models of Ford, Opel, Skoda, Seat and VW you will find electro-hydraulic servo systems. Roughly speaking, the only difference between this and the mechanical hydraulic system is that the power steering pump is electric and thus can be turned on and off as needed. 
Electrohydraulic rack and pinion (Triscan-no.: 85102400105) - suitable for Opel Astra and Zafira

Electric power steering pump (Triscan-no.: 851524625) - suitable for Opel Astra and Zafira
Another option is the electromechanical rack and pinion. Here, the work of the hydraulic system is taken over by an electric motor mounted directly on to the frame. The electric motor is activated only in situations where a "helping hand" on the steering wheel is required. This type of rack and pinion is available for models of Chevrolet, Dacia, Mitsubishi, PSA, Renault, Smart, Suzuki, VAG.
Electromechanical rack and pinion (Triscan no .: 851029439) - suitable for VAG vehicles
Electric steering shafts - EPS (Electric Power Steering)
EPS technology is now widely used in micro, mini and mid-range cars such as the Fiat 500, Hyundai I10, Nissan Micra, Opel Corsa and Renault Scenic. The electric steering shaft is mounted in the vehicle and controlled by the ECU of the car. The steering shaft is attached to a manual rack via a collision-proof shaft.
Electric steering shaft suitable for the Fiat Punto