What is brake corrosion?

A corroded brake caliper

Over time, it is inevitable that some of your car’s many parts will be subject to corrosion.

When your car sits in a wet area for long amounts of time, surface rust will begin to form on the brake discs/rotors. This is completely normal and the rust will go away when you drive again. However, excessive rust on the brake pads, shoes or other components can affect your car’s safety and lead problems.

When the brake pads or shoes begin to develop rust, they will lose their ability to slow your car down. This can affect your vehicle’s overall safety by increasing your stopping distance. For this reason, it is important that the problem is fixed as soon as possible. Most mechanics will routinely inspect your braking system for rust when it is time for a service or Warrant of Fitness. For minor rust, they may spray the rust with brake cleaner. For more major forms of corrosion that can affect the car’s stopping ability, further actions are often required.

Warrant of Fitness requirements for brakes in NZ

Corrosion can also occur in the brake lines, where brake fluid travels between the master cylinder and your braking system. This can eventually lead to a leaking brake line, which will cause you to lose brake fluid and affect your car’s braking ability.


Signs of brake corrosion:

  • Increased stopping distance – When the brakes begin to rust, they can affect your car’s ability to brake quickly and smoothly. This can cause your car to take longer to slow down or come to a stop.
  • Leaking brake fluid – Rust can affect the integrity of parts such as the brake lines or brake calipers. This will often result in brake fluid leaking out. If you notice small puddles accumulating around your car’s wheels, it is a good idea to further examine for leaks in your braking system and check your brake fluid levels.
  • Vibrations and noises – Corrosion on the brake rotors can lead to the surface becoming uneven (pitting). This can cause a squealing or grinding noise when the brakes are applied. It can also cause the vehicle to vibrate while braking.
  • Visible rust damage – If you notice that a lot of rust is forming on the brake discs, shoes or caliper, it may be a reason for concern. Regularly cleaning rust away will prevent it from accumulating, saving you from expensive brake damage.


Have you failed your WOF for brake corrosion?

Brake corrosion is one of the most common causes of a failed Warrant of Fitness, especially on older cars. When you fail your WOF due to brake corrosion, a mechanic may recommend the following:

  • Brake caliper replacement – Brake calipers apply pressure to your brake pads, squeezing them against the rotors and slowing your car down. The brake caliper can corrode due to high amounts of heat and friction, meaning may apply less pressure. A mechanic may recommend that it is replaced to ensure your brakes continue to work properly.
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  • Brake pad replacement – The brake pads make direct contact with the rotor and slow your car down. Over time, the friction material can become corroded or damaged. A brake pad replacement will ensure there is a necessary amount of friction material to safely slow your car down.
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  • Brake line repair – The brake lines are responsible for transferring brake fluid. If they become corroded, they can fail at any time. If you fail your Warrant of Fitness due to corroded brake lines, they must be repaired in order to prevent unexpected leaks and failure in the near future.
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  • Brake rotor replacement or resurfacing – Depending on its condition, the brake rotor may need to be resurfaced to provide a smooth, rust-free surface for the brake pads to grip onto.
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Brake Repairs in Hamilton

If your brakes are corroded and in need or a repair or replacement, we can help you!

Most individual brake components such as discs, pads, and calipers can easily be replaced. Depending on the level of corrosion, we can sometimes sand and repair brake lines. However, we will need to inspect your vehicle before we can promise anything.

For brake repairs, replacement and servicing in Hamilton, contact Grimmer Motors today!


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