Vehicle brakes are one of the most used parts of a motor vehicle and involve some of the more critical safety systems on-board. Failing brakes can cost you dearly, but most issues give you plenty of warning before complete failure occurs.

While a Warrant of Fitness (WoF) inspection will check the performance of the brakes on the day, it’s not an invasive inspection, so nothing is dismantled to monitor their wear or indicate how long the components are likely to last.

It’s up to the individual to ensure that their vehicle is routinely maintained and the brakes are checked with every service (or if an issue is suspected).

Bare minimum not always ideal - the brakes could still squeal

Noisy brakes are one of the most common braking system complaints a vehicle driver will notice. This can be caused by previous work, worn brakes or it could be an early warning that attention is required.

The quality of brake discs or drums can sometimes be overlooked by those wanting a quick replacement on the cheap, where the vehicle simply gets some new pads or shoes thrown in. This is far from ideal, because when brake friction material wears, it can score the steel surface leaving large grooves around the centre and edges.

If a new flat pad/shoe surface is placed against the scored steel surface, the brakes will be quite noisy and may take a long time to wear in and operate as required.

Brake discs don’t always require replacing though. This is why there are companies that offer brake disc skimming services, which essentially use a lathe that mills the surface of the disc at a rate of .02mm at a time to keep it flat. This is all well and good, but there will come a time when the disc rotor reaches the end of its serviceable life and will require replacement. This is determined by a minimum thickness specification that’s stamped on top of the disc by the manufacturer or consulting the vehicle manufacturer’s specifications.

A pulsing pedal

If the brake pedal starts pulsing underfoot when slowing down from higher speeds, it’s likely an indication that the discs have overheated and are now warped.

This can often happen after heavy-footed braking down long hills, or after towing heavy loads. Depending on the extent of damage, you may get away with a disc machine/skim, otherwise, you’ll be looking at a fresh new pair of discs and pads.

Spongy pedal or excessive travel

If your brake pedal doesn’t feel as firm as it used to, you hear noises when you brake, and you are constantly topping up the brake fluid, then you could have a leak.

There are a few common sources of leaks from wheel cylinders to callipers pistons, to the brake master cylinder. The longer you have a vehicle, the more likely that one or all of these would require a rebuild or replacement at one point.

Also, don’t forget to check the condition of the brake fluid itself. Brake fluid is hydroscopic, meaning it absorbs moisture from the atmosphere. Brake fluid with high moisture content can corrode the system from the inside out and can boil, resulting in brake fade. We recommend replacing your brake fluid at least every two years.

Regenerative Braking

Electric and Hybrid vehicles still have brakes, however they do tend to last a lot longer if brake regeneration is activated.

When you decelerate by taking your foot off the throttle, the electric motor stops supplying power so the vehicle will slow down. When the motor stops, it immediately disengages and then starts running backwards. The transmission is still in Drive, so it doesn’t reverse the wheels - instead, it acts like a generator. It captures the kinetic energy from the wheels as they slow down, and converts it into electricity. It’s then stored in the battery to be sent back to the electric motor when it’s needed to drive the vehicle’s wheels.

Under heavy settings, the brakes are seldom required to slow the vehicle as the regeneration slows the vehicle to a stop if there is room enough. This is referred to as ‘one-pedal driving’.

No issue is too small to ignore

There are a number of important braking components that should be reviewed by an experienced vehicle mechanic on a regular basis.

A full brake inspection should check a number of things, including the wear of friction materials on pads and shoes, as well as the condition of rotors and drums. It should include a calliper examination, ensure your lines and hoses haven’t corroded, perished or been damaged. An inspection will also make sure nothing is leaking or has seized, including the park brake mechanisms and wheel cylinders. We recommend visiting aa.co.nz/service to understand what type of service is best for your vehicle, and how regularly you should have it serviced.

So, no matter what you use your car for, you should always ensure that your brakes are in good shape. The last thing you need is to be stranded on the side of the road in the middle of nowhere, or worst case, unable to make it to your destination due to an accident caused by a poorly maintained vehicle.

How can the AA help?

• AA Auto Centre - aa.co.nz/autocentre
• AA Roadservice - aa.co.nz/roadservice

Vehicle experts you can trust