I am working through replacing my power steering pump, gear box, pressure and return lines in my '90 F150 with the 5.8L.

When I bought the pressure and return lines, there is what looks like a nylon washer on the pump side of the pressure line; however, both fittings going into the steering box have nothing. They are the flanged tube with a metal threaded piece (similar to a brake line fitting).

So, are there any teflon o-rings that go around the metal threaded portion of the lines going in to the steering box or do those just get tightened and the compression from being tightened will keep it from leaking?

 

The steering box uses standard flare fittings. They go in just like they are, steel to steel.

The line going into the pump is some goofed-up design that uses a teflon sealing ring to seal up the outside diameter of it. You'll want to put that teflon ring in the sun or gently warm it up with a heat gun before putting it on the fitting.

Just so you know, inside that same goofy fitting there is an o-ring that seals the steel line to the nut. Don't overtighten when connecting it to the pump or it'll crush that o-ring and it WILL leak. I know because mine started spewing and I went and bought a used line that was obviously not leaking, but not knowing about that o-ring I snugged it up like any other hydraulic line and it sprayed oil everywhere just like the last one.

I am gonna replace the pump with a better one someday so I just welded the nut to the line and screwed the whole thing into the pump before connecting it to the steering box... no more leak.

 

Great information. Thank you Dixie. I figured the lines into the steering box were steel to steel. I will look at the nylon/teflon washer on steering pump side again. Could this be in place of having to install a standard o-ring?

 

I'm not sure, it's a strange and (IMO) overly complicated design. But if you do happen to mess up the teflon ring you can pick up a variety pack at your local discount parts store.

 

Here's a good article about the various fittings you'll find on modern cars and trucks.

Your power steering should have an inverted flare style or 45 degree SAE flare fitting on the pressure side IIRC.

Automotive Fittings - Street Rodder Magazine