Brakes Squeaking

What's happening

Most likely causes

1. 1

   Morning moisture and light rust

   Overnight surface rust on rotors squeals for the first few stops, then clears.

2. 2

   Worn wear indicators

   A metal tab designed to squeal when pads are thin. This one means replace soon.

3. 3

   Glazed pads or rotors

   Hard stops overheat the pad surface; it squeals until resurfaced or replaced.

4. 4

   Missing anti-squeal shims or hardware

   Cheap pad jobs skip the shims and squeal forever.

How to diagnose it — in order

1. 1

   Note when it squeals: only the first stops of the day is normal rust.

2. 2

   Look through the wheel at pad thickness; 3mm or less means replacement time.

3. 3

   If it squeals constantly and loudly, the wear indicators are talking.

4. 4

   Check for a shiny glazed look on the pads and rotors.