The brief
The X1 came in for routine maintenance, and the inspection that comes with it caught the front brakes well past due: the discs heavily grooved and the pads worn beyond their operational limit. The owner had them done there and then, which is exactly right, brakes past their limit aren't a put-it-off job. The front brakes do most of the work on any car. The pads are the wear item, designed to be used up and replaced, and the discs they clamp wear too, thinning and grooving over their life. When the pads run past their limit, the wear runs hard into the disc surface, gouging deep grooves. By that point you're not just changing pads, the discs are grooved past serviceable, so the front needs pads and discs together.
The diagnosis
On the lift the front brakes told the story: the pads worn past their limit, and the discs heavily grooved and 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 BMW-spec pads and discs on both sides together, because you don't fit fresh pads to a grooved, 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 BMW-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 grooved-disc grind gone. The X1 went home stopping properly again. Pads run past their limit turn into deeply grooved discs, so doing the front pads and discs as an axle set with genuine parts put the braking back where it should be, the safety job you don't put off.
