Hydroboost fitting size?

Hi all,
I’m try to install my hydroboost. It came out of a 95 F450. It has two high pressure ports and a nipple return. One is supposedly 16mm 1.5 pitch and the other is supposed to be 18mm 1.5 pitch, correct? I am using a pair of Aeroquip adapters to convert to -AN. The 16mm adapter goes in okay but I’m having problems with the 18mm. I can get it about 1 thread in before it binds, almost as if the pitch on the threads aren’t right. I have not tried to “force it” in. Any suggestions?
Thanks!

UPDATE: my hydroboost unit ports are standard, not metric. It's 11/16" and 5/8", not 18mm and 16mm. I'm sure someone will run into this problem some time in the future so just wanted to pass it on. I can't be certain what year my hydroboost was originally installed in.

Another UPDATE: Those ports are still o-ring, but almost all of the 11/16" to AN adapters are inverted flare. There are a couple of options that are o-ring to AN that will fit, but they are aluminum, which I don't want sandwiched between my hydroboost and a steel fitting. The best option is Weatherhead 1444 which adapts from 11/16" o-ring to 5/8" inverted flare (you can get it at NAPA and hydraulic supply joints). The 5/8" o-ring port on the other side of the hydroboost can be adapted to inverted flare using one of those little brass inserts. Then both ports can use a 5/8" inverted flare hose end.

I went through something similar on Big Blue.  See if this post, and maybe the preceding several posts, help: https://forum.garysgaragemahal.com/Hydroboost-Planning-tp7474p51319.html.

Thanks, Gary, I read through the first several pages where you handled the hoses and I didn't really find any confirmation or additional info. I'm specifically talking about the ports on the Hydroboost.

Again, my understanding is it is supposed to have two different sized ports, one is supposed to be 18mm x 1.50 and the other 16mm x 1.50. I don't have the original hose so I can't confirm what was on the truck I pulled the hydroboost from. Can anyone confirm what these port sizes are?

I fit a 16mm into one (extremely snug), but the other doesn't seem to want to take an 18mm beyond the first thread.

Here's a thread that talks about using 11/16 and 5/8 fittings for that port (he references a 97 Superduty). Did they move away from metric on the later units?

https://classicbroncos.com/forums/showthread.php?t=209437

Well, I might as well make this whole post about PS hose since that seems to be where this is going anyway.

I am making my own stainless PTFE hoses for the PS and hydroboost system. All the hose ends will be steel flare female and I'll run steel adapters on the high pressure stuff. For background, I'm using a heavy duty Saginaw dual return PS pump, stock gearbox, a filter and a cooler built into my radiator. I'm also making the low pressure line out of PTFE but will likely fit aluminum hose ends and adapters on those.

In stock applications, the pump to hydroboost line has a bigger ID (and fittings) than the line that runs from the booster to the gearbox. Do I need to make that line 8AN if I'm making the booster to pump line 6AN? Or can they both be 6AN?

I'm intending to run the filter and cooler off the gearbox return since I thought that would see the most flow from the return line. Correct?

The radiator I want to use is the trans cooler built in to my radiator. The outlets are in line vertically, one at the top and one at the bottom. I haven't installed it yet, so I don't know exactly whether the upper radiator port is above pump. I was assuming I should use the same principle as coolant and use the upper port as an inlet and the lower port as an outlet to return to the pump. I haven't exactly squared the physics of it in my head, but does it matter whether the top port of the radiator is above the PS pump? Does it matter if the top port is the inlet?

Also, I ordered some 11/16 and 5/8 adapters for the HB; I'll update here on fit.

I cannot find the fitting sizes in my threads, plural, so can't answer the question about that.

But on the filter, yes the steering side of the system will have by far the most flow.  In fact, the brake side only flows when you are braking.  So you want the filter in the steering side.

On the radiator, since the hot engine coolant comes in the top and the cooler coolant comes out the bottom I'd think you'd want your power steering fluid to flow the same way - in at the top and out at the bottom.  That way would seem to give you cooler fluid.

Will you have a temp sensor monitoring the temp of the fluid?  I ask because I wondered about using the radiator but instead just used the frame-mounted PS cooler.  So I'm curious what kind of temp you'll see.  However, I have nothing with which to compare, so wouldn't know if yours is cooler than mine or vice versa.

Thanks, Gary. I had not planned on putting in a temp sensor on the PS, but I don't think it would be a bad idea. I could put in a T for it and route it to my gauges.

What limited info on the topic I can find leads me to believe that the ideal temp for PS fluid is about 180*, or roughly the same as engine coolant temp. If so, it seems like a waste to not use the coils built into my radiator for it. If anyone has contrary info, would love to hear it.

Little late but what cooler is used when the hydro unit is installed on the factory car / truck?

As far as I can remember only Ford used coolers on the PS systems.
In the late 60's they had a fin cooler just off the pump at the top of the motor.

On our trucks the cooler is just a metal line run from the pump dose across the front cross member for ever how well that cools.

In my book what ever the factory used with that hydro system is what I would use.
BTW I had a GM truck that used hydro brake system and I dont remember any cooler on it and I had the truck from 86 to 02
Dave ----

FuzzFace2 wrote

Little late but what cooler is used when the hydro unit is installed on the factory car / truck?

As far as I can remember only Ford used coolers on the PS systems.
In the late 60's they had a fin cooler just off the pump at the top of the motor.

On our trucks the cooler is just a metal line run from the pump dose across the front cross member for ever how well that cools.

In my book what ever the factory used with that hydro system is what I would use.
BTW I had a GM truck that used hydro brake system and I dont remember any cooler on it and I had the truck from 86 to 02
Dave ----

The diesel trucks Ive seen the 7.3`s with hydroboost brakes they had a tube and fin cooler mounted infront of the condenser.  But that is also for a F250 with its heavier hauling capacity.  If you are putting it on a F150 and not exceeding the hauling capacity of your truck itself then I dont see where the factory powersteering cooler would be a hinderance.

We've installed hydroboost systems on cars and trucks at work, aftermarket stuff and none of the aftermarket kits came with powersteering coolers nor did their paperwork ever mention coolers not even a recommendation.