ps pump pressure line nut?

[babowc]

well,today, i was tearing apart on my ps pump b/c it was busted..and i came across this one huge nut that i could NOT fit any of my sockets/wrenches on..pictured :

i tried a 22mm wrench, its not big enough..anyone have a suggestion?i heard a vise grip.. but i didnt want to take the chance of messing up the nut.

lmk!! its the thing circled in yellow

[babowc]

found out its a 15/16 nut.

[NISTECH]

24mm to be precise