Saginaw 800 steering box

[48builder]

Looking for help with running my steering lines.

I put a quick-ratio steering box in my '48 that I got from a late 80's early 90's Firebird. It has the metric type hoses with the o-rings on the fittings. I have new Russell adapters to go from the o-ring to -6 AN fittings. On the 16MM opening the old fitting goes in and out no problem but the new one doesn't want to go in. I ordered a thread chaser but these adapter fittings should work, correct? they appear to be correct. The old fitting spins right in but the new adapter gets stuck after a half a turn.

The pump on my LT has a remote reservoir. The fitting on the pump outlet is 16MM. Does that high-pressure hose go to the 18 or the 16 MM size on the steering box? The old hose I have has 16 on one end and 18 on the other but I don't know which end went where.

I bought a Trail-gear custom hose set with AN fittings and they will work for the high-pressure side but the braided hose that came with it won't fit on the plastic return tube on the reservoir. Any suggestions for an adapter from the high pressure hose to the plastic fitting. Looks to be 5/16.

Lastly, the reservoir fitting for the return line to the pump is 3/8. All it does is supply fluid back to the pump which has a metal fitting the same size. I need a very flexible hose or a couple 90-degree fittings to make the turns. Looking for suggestions there as well. What type of rubber hose is OK to use with power steering fluid?

Thank you

[kb426]

The only part that I'm helpful with is the return hose. This is what I use: https://www.rockauto.com/en/moreinfo.php?pk=78273&pt=1001647&jsn=7
I had to buy 25' which should be a lifetime supply but nobody had any in the parts stores where I am.

[kb426]

I don't know much about your combination of parts but this page has a good assortment of parts that might be helpful: https://www.detroitspeed.com/products/steering/power_steering_fittings/
I don't know if this is correct but the pressure port was listed as 11/16 x 18 and the return port was 5/8 x 18 for thread size.

[enjenjo]

I think if you check the adapter actually has  16mm by 1.5mm threads. Some Firebirds at that time still used American threads. the two threads mismatch diameter by 0.0049" and 0.002" on the thread pitch.

There are other possible combinations. Some boxes used a 11/16" by 18 front pressure fitting and a 5/8" by 18 return fitting. The later boxes used 18mm pressure fittings and 16mm return fittings.

Chase the adapter threads with 5/8" by 18 thread chaser, and it should fit. BUT check both sides with a bolt and nut, because it's possible to have one the goes the other way, metric box and American adapter

Look at the box in the car. Pressure is the most forward fitting and Return is the most rearward fitting no matter which threads it has.

Outside of that and the internal parts, and the box mount, they are all the same

Most GM cars use 3/8" high pressure hose and 3/8" low pressure return hose

[48builder]

I knew you guys would have all the answers. Thank you very much.