Brakes are polite — they warn you in stages, and each stage is cheaper than the next. Grinding metal means you're past the warnings and into rotor-and-caliper money. Here's the escalation ladder we see at the shop, cheapest symptom first.
1. The morning squeal that goes away
Overnight moisture puts a rust film on rotors, especially in our climate. A squeal for the first few stops is normal. Squeal that persists after the car warms up isn't — that's usually the wear indicator, a small metal tab designed to make noise when pads get thin. Cheap fix if caught here: pads only.
2. A high-pitched squeal that stays
Persistent squealing usually means pads at or near the wear tab. Some pads squeal from glaze or cheap compound, but you can't tell without measuring — our brake inspections are free for exactly this reason.
3. Pulsing through the pedal
A pedal that pushes back rhythmically at speed usually means rotor thickness variation or runout — the rotor isn't perfectly flat anymore. Sometimes it's a dirty hub face or uneven lug torque, sometimes the rotor's done. A dial gauge settles it in minutes.
4. Pulling to one side under braking
One caliper doing more work than the other — seized slide pin, sticking piston, or a collapsed hose. It wears your pads unevenly and lengthens every stop. Not one to sit on.
5. Long or spongy pedal
The pedal travels further than it used to, or feels soft. Could be air in the lines, old fluid that's absorbed water (boiling point drops, pedal goes mushy — common at 3+ years), or a master cylinder starting to bypass. This one skips the queue — book it.
6. The steering wheel shakes when braking
Front rotors again — warped-feeling shake under braking is almost always front-axle. (A shake that happens without braking points at tires or suspension instead — different department, our suspension and alignment page covers that.)
7. The grinding
Metal on metal: pad material gone, backing plate machining the rotor. At this point it's pads plus rotors minimum, plus whatever the metal shrapnel damaged. The warning signs above exist so you never get here — each one was a cheaper conversation.
The five-minute check that helps
Once a month, look through the wheel spokes: you can often see the outer pad against the rotor. Less than ~3 mm of friction material visible means it's time. Edmonton tip: after winter, slide pins seize from salt — even healthy pads can't do their job on seized hardware, and that check needs a lift.