Brakes
When Should You Replace Brake Pads?
Brakes give you plenty of warning, in a fairly specific order. Knowing the difference between a squeal and a grinding noise is worth real money, because one of them means the bill is growing every time you brake.
What this guide covers
The Noises, In Order of Cost
A high squeal when braking
Most pads carry a small metal tab positioned to contact the disc when the friction material gets low. The squeal is that tab doing its job.
This is the system working correctly. It means the pads are near the end and it is time to book in, not time to panic.
You typically have a reasonable margin at this point, but it is not indefinite.
A grinding, metallic noise
This is a different situation entirely. Grinding means the friction material has gone and metal is contacting the disc.
Every stop from here is machining grooves into the disc. A pad job becomes a pad and disc job, and if it continues, the caliper can be damaged too.
The cost is climbing while you drive, which is why this one should not wait for the weekend.
A squeal when reversing or on the first stop of a damp morning is usually surface rust burning off the disc and is normal. A squeal that appears consistently under braking at any time is the wear indicator.
A rhythmic pulsing through the pedal
That is thickness variation in the disc, generally caused by heat. It is felt rather than heard and gets worse with speed.
Measurement decides whether it is skimmed or replaced.
What You Can See
On many cars you can see the outer pad through the wheel spokes.
A new pad has roughly 10 to 12 mm of friction material. Most manufacturers set a minimum around 3 mm, and below that it should be replaced.
Eyeballing gets you a rough idea. It does not replace measuring, and a proper inspection measures both pads on each side, because they wear differently.
How It Feels
- A longer pedal travel or the car taking further to stop.
- Pulling to one side under braking, which usually means one caliper is dragging or not applying.
- A soft pedal after repeated heavy braking, which is usually the fluid rather than the pads.
- A pedal that slowly sinks under steady pressure, which is a hydraulic leak.
That last one is the only symptom on this page that means stop driving. The rest mean book it in.
The Uneven Wear Problem
When one pad is worn out and its partner on the same caliper still has material, that is not random.
The caliper slides on pins so both pads are pressed evenly. Heat, dust and sand seize those pins, and then only one pad does the work.
In Abu Dhabi this is common enough to be worth expecting rather than treating as unusual.
Cleaning and lubricating the sliders is part of a proper brake service. Skipping it is why the same uneven wear returns on a new set of pads.
The Warning Light
Many cars carry a brake wear sensor that triggers a dashboard warning.
The sensor works by being worn through, which is why it is single-use: once it has triggered, it is consumed and has to be replaced with the pads.
Fitting new pads to an old sensor leaves a light that never clears and a system that can no longer tell you anything.
How Long Should Pads Last Here?
Published figures assume a lighter duty cycle than Abu Dhabi provides.
Weight, heat and stop-start traffic all shorten pad life, and towing shortens it further. A heavy SUV in city traffic will get through pads considerably faster than the same vehicle on open roads.
Rather than a number, ask for the measurements at each service. That turns brakes from a surprise into something you can see coming.
Exotic Auto Services shares those figures as a matter of course. For costs, see our luxury car brake service cost guide.
What Else Gets Checked
- Disc thickness against the minimum stamped on the disc.
- Disc runout, which is what causes pulsing.
- Caliper sliders and pistons for free movement.
- Brake fluid condition, because moisture lowers the boiling point.
- Hoses, which swell internally with age and give a soft pedal with no leak.
Pads are the visible part of a system with several other wear items, and a brake service that only looks at pads is not really a brake service.
Frequently Asked Questions
What does squealing brakes mean?
Usually the wear indicator: a small metal tab that contacts the disc when the friction material gets low. It is the system working correctly and it means book it in rather than panic. A squeal only when reversing or on a damp first stop is normally surface rust burning off and is not a fault.
Is grinding when braking serious?
Yes, and it is a different situation from squealing. Grinding means the friction material is gone and metal is contacting the disc, so every stop is machining grooves into it. A pad job becomes a pad and disc job, and the cost is increasing every time you brake, so this one should not wait.
How thick should brake pads be?
A new pad has roughly 10 to 12 mm of friction material and most manufacturers set a minimum around 3 mm. You can often see the outer pad through the wheel spokes for a rough idea, but a proper inspection measures both pads on each side because they frequently wear at different rates.
Why did one brake pad wear out before the other?
Almost always a seized caliper slider. The caliper slides on pins so both pads press evenly, and when heat, dust and sand seize those pins only one pad does the work. In Abu Dhabi it is common, and cleaning the sliders is part of a proper brake service rather than an extra.
My brake pedal feels soft. Is that the pads?
Usually not. A pedal that softens after repeated heavy braking is generally brake fluid that has absorbed moisture and lost boiling point. A pedal that slowly sinks under steady pressure is a hydraulic leak, and that one means stop driving rather than book it in.
