Perhaps nothing sends chills down a driver's spine more than the thought of losing braking ability at speed, and any strange behaviour or changes in performance you experience while braking should be diagnosed and repaired as quickly as possible. However, many causes of brake trouble aren't so easy to diagnose, and the only clue you might have that your brakes are not working as they should is a strange noise. Different noises during braking can indicate different underlying problems:
Squeaking and squealing noises
A persistent, high pitched squeak or squeal coming from your brakes when you engage them can signify a number of problems relating to wear and tear.
However, your first priority should be to check on the state of your brake pads, as many are fitted with indicator tabs that are designed to protrude from the pad once it has reached the end of its safe working life. These tabs produce the whining noise deliberately by coming into contact with the brake drums and are a clear indicator that your brake pads need prompt replacement.
Having said that, you may be hearing an unpleasant squeak when you brake using brand new pads; this generally signifies that you probably should have spent more on them. Cheap brake pads generally contain high quantities of metal fragments which can provoke intermittent squeaking.
If you hear grinding noises when you engage your vehicle's brakes, you should pull over as soon as you can do so safely -- this noise can indicate one of two dangerous braking problems:
- Perished brake pads: Running on worn or badly-aged brake pads for too long can cause them to wear through entirely, and the metal of the braking shoe is exposed directly to the metal of the braking rotor. This can badly undermine your vehicle's braking ability, and will cause severe damage quickly due to the massive buildup of heat and friction inside the stricken drum. Take your vehicle off the road immediately, and have professional brake repair services inspect your drums and shoes for any lasting damage.
- Rocks and debris: A less serious but still potentially damaging problem, grinding brakes can also be caused by a stone or other piece of road detritus becoming lodged in your brake, between the wheel housing and the rotor. This grinding may become louder when turning corners, but shouldn't cause any last damage if you have it removed quickly.
A dull, intermittent thump is one of the more unusual braking noises drivers encounter, and may be completely benign. Many new brake pads can cause a mild thumping noise whn engaged, as their new high-friction surfaces cause the braking rotors to stop quickly and jarringly. However, if you haven't had your brake pads replaced recently, you should have your brakes professionally inspected, as this thumping can also be caused by rusted brakes. Parts of the brake that come into contact with the pads are particularly vulnerable to rust, as are brakes on vehicles that are routinely left outdoors.