Poseidon HP gauge service?

[Fibonacci]

As posted recently, I've just dipped my toe in the Poseidon regulator scene...
A cheap early Cyklon 300 (2980?) first and second stage with Poseidon HP Imperial gauge just arrived in the post to practice on!

The HP gauge seems in very good condition, but the o-ring was hard and brittle needing replacement.
The swivel end of the HP hose has an internal 5mm hex drive but not sure if its got an o-ring seal or not, doesn't seem to use a spool.
Is the front glass bezel screwed on and the o-ring serviceable?
Anyone know the correct sizes?

 

[Fibonacci]

OK some progress...
The swivel end of the hose does indeed have an o-ring accessed via unscrewing the spigot with a 5mm hex... need to grip the hose end in a vice protected by leather pads as there is no integral hex on the crimped end to grip with a spanner like on modern HP hoses.
The swivel spigot is 7.0mm OD,
A 7.0 x 2.0mm 90 Duro o-ring fits the internal recess (ID 9.5 x 2.0mm) slightly too tight, so may try a 6.5 x 1.5 or 6.5 x 2.0mm.
The second o-ring seals the lower gauge threaded boss (9.6mm OD) to the static part of the hose swivel, the recess ID is 11.5 x 1.5mm
Still working on the front glass seal...

 

[IslandKraut]

Good luck getting the glass cover off. I was able to do it, but it took quite a lot of torque with padded wrench and the ring in a padded vice. And I have not tried to see if it is water proof yet as it is more of a display piece. In my case it was necessary as the glass / acrylic had hazing I needed to micromesh off (which it did nicely). Yours actually looks nicer than mine did, so I wouldn't necessarily mess with it.

As for the swivel - mine didn't. It sealed with a nylon gasket like the ports on the old "metric [not]" first stages.

Oh and that SPG will screw right into one the HP port of that first stage for a nice garage regulator setup or bail out bottle without needing a hose.