Diving Concepts Neo Z Back Zip Drysuit valves

[emoreira]

Hi, I have just bought a new (although it has several years already) Neo Z Back Zip DC crushed neoprene Drysuit.
It has never been used, never wet.
I understand that Diving Concepts is already gone out of business.
The valves has the DC logo, no clue of the valves manufacturer.
If any one has any info about the valves, how to overhaul them, much appreciated.

 

[emoreira]

It seems that those valves are APEKS valves with the Diving Concepts logo.
Found APEKS manual, however there is no disassembly procedure of the valve itself.