With a 1997 Ford F150 when pressing hard on the brake pedal it feels very soft. The brakes work but feel soft instead of stiff. Could it be a Master Cylinder problem?

Answer 1

That is a possibility, but like most potentially expensive or difficult repairs, check the cheaper stuff first. The problem may be that the brake fluid is old and water contaminated. In modern ABS braking systems, water in the fluid can really soften up the feel of the pedal.This can be tested at most any brake shop (usually free) and either you can flush the system yourself (pain in the butt) or many brake shops have machines to do it now for about $100. There may be a leak in the system somewhere that either allowed the reservoir to get low enough to suck air, or is simply letting precious hydraulic pressure (and fluid) escape. Not all leaks are immediately visible, so check carefully, caliper piston seal and rear brake cylinder seal leaks are hard to spot without removing wheels and drums, so do that before jumping to conclusions. Another common possibility is that the rear brake shoes have not been adjusting properly, causing the cylinder pistons to have to travel further, which uses up pedal travel making it feel soft. The shoes should be so close to the drum that a piece of paper won't fit. They are supposed to self adjust, but for whatever reason this doesn't always happen, and when they're too far out of adjustment they simply cannot adjust themselves.