The O-ring seals within the female, socket half of the quick connect occasionally blow out or deteriorate. Allowing the pump to operate without the hose or nozzle attached is a common cause. If leaks occur, simply replace the O-ring seal.
Some pressure washers (Karcher, TroyBuilt...) are equipped with 22 mm couplers similar to garden house connections. Always tighten this type of connection securely.
||Male National Pipe Thread
||Female National Pipe Thread
||22 Millimeters, or 7/8"