The hydraulic unit, either a caliper for disc, or wheel cylinder for drum brakes, or the line has a leak, part replacement is the only fix.
Aug 1, 2010 at 10:14 AM
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.