I've looked everywhere but can't find any threads with my type of scenario.

I started out, with replacing a worn, sloppy, leaking steering box with a Lares steering box from rockauto.com. After I got it and installed it. The steering worked fine but when I went slow such as in a Parkin lot of pulling in driveway. If I have it gas, it would work. The power steering would stop.

So, bein that I replaced the box, I decided it was probably the pump. Replaced the pump with a reman from rockauto and it still did the exact same thing.

So, i decided it had to be a defective gear box. So I sent the one back and got another apon warranty. Put it in today and bled the system. Dropped back on the wheels and turning in the drive way. It worked great. No problems at all. Pull out of the drive and get to the stop sign 100 yards down the street and this time I have NO power steering at all. None.

Pulled it back into the drive and spent an hour tryin to bleed it turning lock to lock at least 25 times.

Also noticed very fine, what looked like metal particles. Can't feel em but the fluid has a sparkle to it. Not sure if this is from the new parts or something that's was left in the lines from the first steering box/pump but it's there. Even with the particles gathered on a magnet, I can't really em. Maybe a little gritty but very fine.

So now I'm stumped. I'm thinkin it's a bad pump but not sure. I don't think lines clogged cause the pump wines likes it's trying to turn but won't. And belt is not slipping. Fluid is new Type F.

 

Are you running the stock ford power steering pump?

Later, Shortbox4x4

 

Yea. I forgot to mention. My trucks a 77 but has the 78-79 pump. So yes it's stock but the later model stock.

 

Saw a post here a month or two ago where someone noticed that where ever he was supposed to be bleeding from, was not the highest point on the box. I think he opened a line or something to get it bled all the way. I also don't remember what year truck he had.

 

Gonna try this and hopefully it'll work. Seems like a big problem with the 78-79 steering. Not sure how I missed all this when I did my earlier research. Thanks

https://www.ford-trucks.com/forums/1...ering-fix.html

 

Sure seems odd that you've replaced the box and pump and still trouble, quite the stumper!. Are you getting any whine out of the pump? no leaks I assume. Did you replace the lines (or blow air through them while off to make sure no debris). Steering isn't binding any (nice turns lock to lock with the wheels off ground).

 

That's the one! Hope it works for you.

 

The pump pressure relief valve is behind the fitting in the pump where the pressure line hooks up. It is more than likey stuck, especially since you saw fine particles in the oil. Might pull it out and clean, and flush the system and try again. I had several that did that after pump replacement.

 

Just tried the link above and no luck. I'll try cleaning the PRV and see what happens. I seem to have no power steering now. And the pump makes no noise when I try to turn.

 

Well I went to pull the pressure relief valve out and it was stuck. So I cleaned it although it didn't look dirty. Drained as much fluid out as I could and put it back together with fresh type F and she's works great. Thanks for the help guys. I never thought about the PRV being that its part of the pump and the pump was a new remanufactured. Thanks