The way I did mine was get a turkey baster to suck out as much fluid as possible from the resivoir while the p/s drain plug on the gear box was out. Then you will see the filter at the bottom of the resivoir. I then turned the steering wheel as much as possible left to right (WITH THE CAR OFF!) to get the excess fluid into the res. Then suck out the rest with the baster. Put plug back in, filter then top off with the fluid of your choice. (I say that because of the myriad of threads that people respond / post with in regards to the use of all kinds of different oils and their applications. If really dirty keep filling and flushig with the above prescribed method. Then enjoy!