Possibly something was reassembled incorrectly, but my best guess is the shoes were too far out-of-adjustment. They will eventually self-adjust, but there is a problem that can show up on any car over about a year old. Because the shoes have to travel so far to contact the drums, you have to push the brake pedal much further than normal. Crud and corrosion build up in the lower halves of the bores in the master cylinder where the pistons don't normally travel. The first time you push the brake pedal further than normal, you run the rubber lip seals over that crud and they are likely to be torn. That results in internal leakage which often takes two or three days to show up. It can start out as a slowly-sinking brake pedal, but more often / eventually the brake fluid bypasses those seals so no brake fluid is being pushed. The fix for that is a rebuilt master cylinder and to adjust the shoes.
This problem will not occur with a master cylinder that is less than about a year old because that corrosion hasn't formed yet. When professionals do anything related to the brakes, like bleeding the system or replacing parts, they never push the brake pedal more than about halfway to the floor.
Thursday, June 2nd, 2016 AT 7:51 PM