adder

Hi all, my first post here

need some help on some problems...

When I'm driving at speeds around 50km/h (ca 30 mph) I get this cyclic, repeating, humming (low base) noise from the rear axle, anyone have a clue to what might be causing this??

another problem...more serious
Last week when braking the pedal started to feel kind of mushy, spongy (air?) and the brakes did not perform, THEN it would not work at all, the pedal went all down and would only use the one system (rear left, front right) and there was some dripping coming from the centre of the car (visible on the ground under the car) obvious leeking of course, BUT the mechanic at the shop cannot locate where the leaking is coming from !!! what is going on here, please anyone ?!