???Power Steering Pump and Gear Box???

[packman]

What would be the best fluid to use for flushing out the power steering system. I have a new pump, but the steering box/gear is 16 years old (replaced in 2004). I would like to flush the system and start anew. Could WD-40 be used to initially flush the system, then backfill it with cheap power steering fluid (Dollar General), run that out, and replace that with decent stuff?

[IPreferDIY]

Power steering systems typically use tranny fluid, which already has detergents and whatnot in it. If you were doing a teardown and cleaning the internal guts thoroughly and drying everything before reassembling with proper fluid, then you could use a solvent or whatever, but using a solvent as a flush runs the risk of the solvent being left behind and contaminating the proper fluid. Stick with the proper fluid. A cheap version is fine if it's trustworthy. If you have doubts about getting all the old fluid out the first time and/or you want things really clean, change the fluid again after you've driven for a bit.

[packman]

^^^^^^^^^^Thank you. I will do just that.^^^^^^^^^^^

[gadget73]

Use Type F. Do not flush it with anything other than transmission fluid. If the pump is off, take both lines and run them down into a catch pan. Turn the wheels back and forth a couple times and most of whats in the box will come out. Hook things up but don't put the belt on. Fill the reservoir and turn the pump by hand. When it stops blowing bubbles back up in the reservoir, fill it back up, put the belt on and start it. Run the wheel end to end a few times and refill as needed.

[Mainemantom]

Gadget, I am glad to reminded me to turn the pimp by hand first before putting the belt on. I am fixing to replace the 90 CV pump. I would not have remembered that step.

[gadget73]

You can skip it, but it takes an awful lot longer to get the air and the noise out if you do. Cheater option, pull the coil wire and use the starter in short bursts. That will get the job done too. You just don't want the pump spinning at full speed or that big air bubble turns into millions of tiny ones.

[sly]

There's also the option of putting the return hose to a bucket, plugging the return bib on the reservoir and running fluid through the system to flush it out. This does require some help as someone needs to be pouring while someone else starts the car and turns the wheels lock to lock a couple of times then turns off the car. You will go through a gallon pretty quick. Did that with the box when I replaced the pump on it the second time and didn't have any issues with it to the day I sold it.