The brake warning light has appeared on the dashboard and doesn't go out when the other lights do after starting the car up.
The low brake pads warning light has appeared on the dashboard and doesn't go out.
The brake pedal isn't lined up where it usually is, the pedal is further away and seems to be half pressed in already.
When braking from a speed the car vibrates and the braking doesn't feel as controlled as it was before.
When braking the car veers off to one side, this happens even on a straight section of road. The car seems to pull to the one side.
When braking the brakes make a squeaking sound, when you take your foot off the brake pedal the sound stops.
When you apply pressure to the brake pedal there is a clicking or tapping sound. The sound can be loud or quiet and usually won't be felt through the pedal itself. It will usually sound like it's coming from one of the corners of the car. The clicking will usually increase or decrease in frequency with the speed of the car, ie it will click aster at higher speeds.
When pressing the brake pedal the brakes don't apply in a smooth way, they seem to come on all of a sudden and are more bumpy than they used to be.