Brake problems?

check brake fluid if its low you probably have a leak somwhere if you cant see anything on the ground then pull the back wheels and check wheel cylinders for leaks and adjust the brakes

are you adding alot of brk fluid? you could have a fluid leak at any wheel or master cyl ck that 1st. your brk booster could be going out if pedal is hard but has no stopping pwr

CHECK BRAKE FLUID IF FULL REPLACE MASTER CYLINDER.