Spray the area with brake clean or other evaporating cleaner/solvent.
They blow dry with air hose, then clean again/dry.
Thoroughly dust the area with baby powder/monkey butt powder or equivalent.
Now watch for the leak, paying attention to the expansion plug in the center, under where the cork gasket lives.(about the size of a fifty cent piece.)
This will tell you if it is the expansion plug or the brake plunger is leaking.
#1 leak is the relief valves up top, and running down.
#2 leak is the cork gasket.
#3 leak is the expansion plug.
#4 leak is the brake plunger.
#5 leak is the suction fitting
in that order.
You don't want to fix the wrong non leaking item.
