Was this just new pads slapped on by a do-it-yourselfer, or was it a complete brake job by a professional? If you add as much detail as possible, I can offer better suggestions, but the first thing that comes to mind is after replacing the front brake pads, the brake pedal has to be pumped multiple times to adjust the calipers, then pedal pressure will build up like normal. Where do-it-yourselfers and inexperienced mechanics get in trouble is they push the brake pedal all the way to the floor. After about the first year of a car's life, crud and corrosion build up in the lower halves of the bores in the master cylinder where the pistons don't normally travel. Pushing the brake pedal over half way to the floor runs the rubber lip seals over that crud and can rip them. That usually shows up as a slowly-sinking brake pedal, and that often takes two or three days to show up. The fix for that is a rebuilt master cylinder.
If anything was done that allowed air to get into the hydraulic system, and someone tried to bleed that out at the wheels, if the car has anti-lock brakes, that air could become trapped in the hydraulic controller. On most cars you need a scanner to command the ABS Computer to open two valves so the air can be bled from those two chambers.
Was the caliper mounting hardware inspected? If the chrome plating has lifted on the slide bolts, those must be replaced. The rust pits can prevent the caliper from sliding freely. This is a less-common cause of low brake pedal, but it can cause the caliper to stick and not fully adjust. Those pins must be lubricated with a special high-temperature brake grease too.
Friday, April 5th, 2019 AT 9:25 PM
