What are these connectors called?

[thegoulais]

 

[oldnslo]

They look like SAE ORB (O-ring Boss) in the valve and female swivel pipe where hose attaches.

depending on valve make also possible could be BSPP in the valve

 

[Zebrafive]

The male ends (in the valve) look like SAE also called ORB (O Ring Boss) the female ends to the hoses look like female swivel NPT (National Pipe Thread)

 

[Rebeldad1]

too many look the same but different. remove them and take them to a hydraulic shop to match them up. will save a trip or two.

 

[SylvainG]

From what I've read, disassembling and reassembling NPT induce leaks so personally, I bought different combinations of fittings and only used the one that I needed and returned the rest.

 

[Big Barn]

From what I've read, disassembling and reassembling NPT induce leaks so personally, I bought different combinations of fittings and only used the one that I needed and returned the rest.

While this is probably true I would liken it to the fact that you are more likely to have an accident driving your car than if you left it parked.

 

[LouNY]

From just a visual inspect I'd say that both post 2 and 3 had the correct answer.
As far as reusing them replace the O-rings (should be less then a dime each) and use a bit of pipe dope on the male threads.

 

[LD1]

Yup, look like standard ole ORB fittings. No thread sealer required