I'm going to recharge my gas spheres!?

Hiya



I'll keep it short as I can, going to recharge my spheres (nitrogen I believe)



As far as I'm aware the nitrogen half was filled to around (16bar/200psi) and the bottom hydrolastic fluid (400psi)



Basically guna drain hydrolastic fluid, an read I'm supposed to drill a hole in the nitrogen half (top) an tig weld a female boss to top an screw in a male schrader valve



My question the top was once filled to (16bar/200psi) how on earth do I know what's left in before I start drilling a hole in? :/



Anyone already done this, is it safe?



How about after doing it did it make your F's ride comfort just abit better or dramatically smoother ride



Regards nick

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