[Closed] Marzocchi XC500's - Servicing, ANY advice

Got a pair of the above, I'd kinda given up on them but thought I'd try servicing them to put on an old bike.

I've got the TST 5 cartridge out along with a lot brown oil but I cant undo the 12mm nut on the left hand leg. I can get a socket on it (just) but the rod just seems to spin in the uppers. Any tips?

What to people think of servicing the TST 5, I've had a wee watch of the video for the marathons.

Edit: It's the '07 ones

Is there any alternative cartridge I could put in as a more reliable replacement? not keen on spending much, just interested to see if I could salvage some use out of the fork.