This could be a few things. First check to make sure the brake fluid is full. Next, have someone push on the brakes while you check the rubber brake hoses at each wheel. Make sure none are expanding. Also, check for leaks at all lines, calipers, wheel cylenders, master cylender. If everything is good, it sounds like there is a problem with the master cylender.
Let me know what you find.
Monday, October 4th, 2010 AT 10:33 AM