I have a problems with my 04 sport 4 runner brakes. the foot brake padel is spongy, so i drain the brake fluid thinking there is air in the lines ( no air bubbles) still the same. On the hwy if i pump on the padel the vehicle pulls to one side, very scary. I have replaced all the pads front end rear. Also need to replace the front axle ball bearings , is it easy to replace the hubs my self or bring it to a shop.