Power steering system on our 2009 F250SD 6.4L has a minor leak at the pump(which is why we haven't fixed it). We inadvertently bought PSF with stop leak and put in it vice ATF. Seems to still be working fine. Should I flush the system or not worry about it? Thx.

 

We'll not all hydraulic fluid is the same some is petroleum based some is silicone based. Bad to mix them. Some trans fluid has friction modifiers in it again bad in a system not designed for it. Also I never get the stop leak stuff it can plug up a leak true but it doesn't discriminate it stops up every small hole and that can be bad. I would just change it and while changing it allow the fluid to drain understandably not all will drain but enough to dilute it down. You aren't going to the moon here you are going to work. Best of luck to you.

 

Do you have hydroboost? If so get that stuff out of there.

 

No hyrdoboost...flushing the system today. Gotta find a good diagram of the flow routing so I break the line at the right point.

Edit: Dang...maybe I do have hydroboost...3 lines from my reservoir...one from cooler, one to pump, one that appears to go back to some type of assembly on top of master cylinder...yuck...thinking about all the connections I might need to break to bleed all air from the system is giving me a mild headache and desire to take it to the dealership...

 

OK...so given that there are two paths...one to hydroboost and one to the steering system...it was too complicated IMO to try running drain and fill (especially without taking a bunch of stuff off so I could get to the two return lines). So I "punted". Used a syphon to empty the reservoir while cycling the wheels and brakes, then refilled with the proper ATF. Put a quart back in today. Will do the same cycle again once a week for the next five weeks(I bought 5 quarts of Mobil 1 synthetic)...it won't be perfect, but the dilution factor should get it nearly clean.

 

I think that should be a fine way of getting it as good as you can.

 

Wonder if this procedure will work for the 6.4L?

Ford Super Duty Power Steering Flush | Superdutypsd.com

 

I don't see why not as long as you have the hydroboost. They did make some that were vacumn brakes.

 

OK...flush complete. 4 quarts Mobil 1 ATF. That procedure for the 7.3 was directly transferable. Yay! (also had to replace an alternator this week...yuck.)