There's two common things that can cause this. The first is after pressing the pistons into the caliper housings to make room for the new, thicker pads, those pistons have to be run back out to adjust them. That is done by stroking the brake pedal a few times. The second problem comes from bleeding the system with a helper pushing on the brake pedal. Bleeding wasn't necessary in this case unless you just wanted to exchange some of the old moisture-laden brake fluid. During either of these procedures, it is common for do-it-yourselfers and inexperienced mechanics to push the brake pedal all the way to the floor. Doing that has a real good chance of damaging the master cylinder. Crud and corrosion build up in the lower halves of the bores where the pistons don't normally travel. Pushing the brake pedal all the way to the floor runs the rubber lip seals over that crud and can rip them. To avoid this possibility, professionals never push the brake pedal more than half way to the floor, and most of us never use a helper to pedal-bleed. Gravity-bleeding is just as effective with little of the risk.
If you had the hydraulic system open, ... Say to replace the calipers or a rusted steel line, and the master cylinder was allowed to run empty, air will have gotten into the lines. If the car has anti-lock brakes, it is likely you'll need a scanner to bleed two chambers in the hydraulic controller. The scanner has a menu selection for bleeding that commands the ABS Computer to open two valves so the air can be expelled from those two chambers.
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Tuesday, July 2nd, 2019 AT 2:55 PM
