The brief
The A1's driver came in complaining of a grinding sound when hitting the brakes. He brought it in, which is the right call, grinding brakes are metal on metal and they're starting to do damage. The pads are the wear item, designed to be used up and replaced, and the discs they clamp wear too, thinning and scoring over their life. When the pads run right down, the squeal turns to a grind as the backing plate contacts the disc, which gouges the disc surface. The A1's front pads had reached that point and were beginning to damage the discs, so it wasn't just pads, the discs were scored past serviceable, the front needed pads and discs together.
The diagnosis
On the lift the front brakes told the story: the pads worn down to the backing plate, and the discs scored from running on metal, below minimum thickness. The calipers and slides were freed off and checked, they were fine, just the pads and discs gone. The rears still had life. So it was a front axle set: new genuine Audi-spec pads and discs on both sides together, because you don't fit fresh pads to a scored, undersized disc, and you do the pair so both sides bite the same.
The work
Both front discs and the worn pads were removed, the hubs cleaned up, and a new genuine Audi-spec set of discs and pads fitted, the calipers and slide pins cleaned and greased so they move freely, every fastener torqued to spec. The pads were bedded in properly so they'd grip evenly from the start. A road test confirmed quiet, even, progressive braking with a firm pedal and no pulling.
The outcome
Quiet brakes, a firm pedal, even bite, sharp progressive stopping, and the grinding gone. The A1 went home stopping properly again. Worn-out pads turn into scored discs the longer they're left, so doing the front pads and discs as an axle set put the braking back where it should be, the safety job you don't put off.
