Wrench size for ford 3000 hydraulic pressure nut

[banc123]

Not sure I can get a cressent wrench in the tight spot below the foot rest. Tractor at a different location and I'd like to make sure I have the right size wrench, leaking and I hope I can just tighten it.

Thanks

FORD 2 3 4 TRACTOR HYD TUBE COMPRESSION NUT OEM NEW HOLLAND C7NNH856C | eBay