It's a bleeder, not a zerk. It helps if you crack it loose with a 6 point socket before you bleed it, that'll keep you from rounding it off. Righty tighty, lefty
loosey. Use a hose from the bleeder to a jar with some brake fluid in it, that'll keep you from sucking air back into the system. Go rt rear, left rear, rt front & then left front. That's so you work your way from the farthest to the ...