You will find all the videos I made about this Mercedes C200 in a Playlist :
   • Mercedes w203 C class - Oxygen Sensor...  

To remove and replace the power steering pump on this Mercedes w203 c200 can be relatively easy ; However to troubleshoot the problems can be tricky .
So one of obvious step is to check the quality of the fluid which can tell you a bit about the power steering pump ! If the fluid have foaming or air after you drove the car , you might have some internal leaks on the pump which allows the pressure to equalize between those 2 fluid lines .
Anyway since a power steering pump can be the faulty part in most of the situations , try to replace the fluid every 50 000 miles or when the quality of the fluid is getting lower .

Disclaimer :
This youtube channel :"do it ! " can not guarantee that this information suits to your car . "do it !" assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. Use this information at your own risk .