2001 Toyota Camry • 4 cylinder 2WD Automatic • 600,500 miles

When I got this car 6 months ago the brakes worked fine. About a month ago, the brake pedal became soft and you had to push farther to get stopped and then you started to need to pump the brakes to stop. I took it to my local mechanic who is a GM Master Mechanic who noticed a small leak in the rear brake lines so replaced them, that worked for about 2 weeks then had the same problem. He replaced the master cylinder with a recycled one to see if that was the problem, but no dice. He says lots of fluid in the master cylinder, fluid going to the rear brakes (bled them 2 twice), and he is stumped as to what the issue is. Wondering if you have any thoughts before I scrap the car.
June 2, 2014.

If the pedal is going to the floor, either you have a leak, brakes are totally out of adjustment, or one of the rubber brake hoses is bad and expanding when you apply the brakes.

Pedal doesn't go all the way to the floor now but almost. My mechanic says there are no visible leaks anywhere, he has adjusted the brakes including the physical pedal itself and still the same issue.I'll ask about the rubber brake hoses.

Jun 2, 2014.
If the brakes are properly bled, the MC is good, the brakes are properly bled, and there are no leaks, I honestly don't know what else it could be other than a brake hose.