Steering Box Fittings

[ntsqd]

Well, I had to go borrow an Inverted Flare tube nut with 11/16-18 threads and it is too big to thread into the port.

Stupid engineers......

 

[rickyrockrat]

LEE MFG. CO in Sun Valley CA
818-768-0371
Lee Manufacturing Company Sun valley, CA 91352 Steering gears Pumps Reservoirs
has
16mm x 1.5 inverted flare to #6jic for the return side and
17mm x 1.5 inverted flare to #6jic for the press side for
$8 each

(Be aware, I still think I might be screwed up on which is the Press Vs return side.)
Those are the fittings sizes tho.

The M16x1.5 is the Pressure port, and is closest to the body (farthest from the steering wheel shaft). I thought I was crazy too when I measured those fittings. One is 14.5mmID (M16x1.5) and the other is 15.5mm ID, which I suppose is the 17MM.

IF you did use the 16MM, you've only got .022 inches at most (that's .011 inches each side) holding that thread in, which isn't much. If you torque it much at all you'll be mangling threads.

If you want to do the math and check it with a fine-thread 5/8 bolt, you will see that:M16 is 16mm/25.4~.630. 5/8=.625, so 5/8 is 5 thousands smaller than 16MM. If it weren't for the threads being too far off, the 5/8 bolt would fit like a charm.

If you look in that pressure port, you will see a flare adapter, which is removable. You can take a smooth piece of steel and gently pry it back and forth and it will start working out of the hole. My theory is that a M16 O-ring hose will fit once that flare is out. I'm ordering a hose to find out.

Since I had a Lathe, I just built my own adapter, then anodized it (I always wanted to know how to do that!). This adapts from the M16x1.5 inverted flare to the M16x1.5 O-ring hose (which I used for my Saginaw P/S conversion).

Now that I've done this one, I went and bought some 6061-T6 Hex bar, since milling that nut was not fun. This was dyed using black Rit clothes die. I think I'll use purple next time.

 

[ntsqd]

Seems like a lot of effort to avoid buying a maybe $20 adapter fitting (including shipping) that is a one-time purchase.

 

[mikeob1]

If I had to guess, the reason for the design was to reduce the likelihood of mechanics and assemblers inadvertently reversing the high and low pressure sides. The design, although inconvenient 25 years later, seems practical and smart to me.

 

[ntsqd]

No doubt that is the reason for the different sizes.

I want to say that I tried an M16 in the larger port and the fit was too sloppy to give me anything close to a warm & fuzzy feeling about it. I have some O-Ring Bump tube nuts in M16 so I could try one of them (again?), but given the supply pressure involved it's going to need to fit well before I would even consider it.

EDIT: I just tried the M16 O-Ring Bump tube nut in both ports. The port nearest the input shaft is too sloppy loose to make a reliable seal, even at low pressure.