My brakes have gotten soft lately, and seem to be getting softer. I am not losing brake fluid, the pads have life left in them, and the rotors are smooth. I checked the booster by the old pump it with the engine off, turn the engine on test, and it passed. If I pump the brakes, the pedal doesn't go down as far, but like I said, no external leaks. I have a constant ABS light because I replaced the front wheel bearings with some i bought off of Ebay. The wiring connection to the ABS sensors was different from original, so I cut the connectors off of the old bearings and soldered them onto the new ones, but the ABS light never went away. I have driven a good 5000 miles since replacing the bearings, and only recently have I had the soft pedal problem, so I don't think it's related, but I guess it could be. Is there a way to test if the master cylinder is leaking internally? I don't want to buy a new one and have that turn out not to be the problem.