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Braking system doís and donítsÖ


The braking system is the most important safety system on your vehicle, so itís important to give it the care and attention it needs to function at its best.  Your well-being depends on it.  A braking system that isnít functioning as intended is downright dangerous.  Hereís a list of doís and doníts for the braking system that will see it performing at peak:


Check the brake fluid level weekly...

Check the brake fluid level weekly at the brake fluid reservoir (on top of the brake master cylinder) when the vehicle is on level ground.  If the reservoir is transparent, allowing you to see the level of the brake fluid, thereís no need to remove the cap from the reservoir.  If itís a bit difficult to discern where the level of the brake fluid is, it can help to push down on a front corner of the vehicle to rock the vehicle so that the level of the brake fluid moves and you can detect it.

You can find more information about checking the brake fluid level in the section titled, Checking the Brake Fluid Level.


Exercise caution to prevent the brake fluid from absorbing moistureÖ

Brake fluid is hygroscopic which means that it readily absorbs moisture from the air.  An accumulation of water in the brake fluid leads to a deterioration in braking performance because the water lowers the boiling point of the fluid in the brake system which operates under high temperature and high pressure.  If the brake fluid in the brake system vaporises as a result of this lower boiling point, the braking performance becomes spongier and less effective.  In order to minimise the absorption of water into the brake fluid, itís important to observe the following points:

  • Containers of brake fluid should be tightly closed as quickly as possible after use and should, in fact, be fully used within twelve months of opening or discarded altogether (in an environmentally responsible manner).  Itís a good idea to use a permanent marker to write on the container the date on which it was opened and the date on which it should be discarded.
  • Donít pour brake fluid from one storage container to another which causes the fluid to absorb moisture from the air.
  • When pouring brake fluid into the reservoir above the master cylinder, pour it in directly from its original container.
  • Donít leave the cap off of the brake fluid reservoir for any longer than is necessary in order to minimise the absorption of moisture from the air into the brake fluid in the reservoir.

Wash brake fluid spilled on the vehicle off with water immediately...

If any brake fluid is spilled onto the paintwork of the vehicle, such as in the engine bay surrounding the brake fluid reservoir, wash it off immediately with water to prevent it from damaging the paintwork.  (Itís obviously important to make sure the cap is on the brake fluid reservoir before washing the area around the reservoir with water, in order to prevent water from entering the reservoir.)  Donít wipe the brake fluid off.  Brake fluid eats into the paintwork, making it soft.  Wiping the fluid off could smudge and damage the paintwork.

In addition to keeping a garden hose close to where your vehicle is parked at home, itís quite handy to also keep a plastic watering can next to the garden tap, which can be used to quickly wash away small spills such as brake fluid on paintwork.


Replace the brake fluid in the braking system every 12 to 24 monthsÖ

Replace the brake fluid in the entire braking system every twelve to twenty-four months irrespective of distance travelled with a high-quality brake fluid suitable for your vehicle to prevent corrosion inside the braking system and to ensure optimal braking performance.  The hygroscopic nature of brake fluid results in absorption of moisture from the air through the rubber seals in the braking system and via the master cylinder reservoir when the cap is removed for topping up the brake fluid.

Water accumulating in the brake fluid over time causes braking performance to deteriorate.  It also provides a means by which corrosion can occur inside the braking system.  Brake fluid contains corrosion inhibitors designed to prevent corrosion of the insides of the metal parts comprising the braking system, such as the master cylinder, the metal brake lines, the disc brake callipers, the disc brake calliper pistons and the rear wheel cylinders in the case of drum brakes, which are often used on the rear wheels.  However, over time, these corrosion inhibitors in the brake fluid are depleted so that corrosion in the braking system can no longer be prevented.  The high levels of heat generated by the braking system exacerbate this depletion of the corrosion inhibitors in the brake fluid.  The copper alloy linings inside the metal brake lines are the first part of the braking system to corrode when the level of the corrosion inhibitors becomes too low.  As a result of this corrosion, copper ions are released into the brake fluid and then act as a catalyst for the corrosion of other components inside the braking system.  A braking system thatís made up of corroded components is neither effective nor safe.

The cost of repairing a braking system ravaged by corrosion of its internal components is quite considerable.  A much better alternative than suffering this kind of repair is to change the entire brake fluid in the brake system regularly in order to absolutely prevent any corrosion from taking place at all.  By replacing the brake fluid regularly with a high-quality brake fluid, the corrosion inhibitors in the brake system are always maintained at a sufficiently high level to prevent damaging and costly corrosion from taking place.

Regular brake fluid changes also prevent the rubber seals in the braking system from deteriorating and leaking fluid.  Not only that, but the performance and effectiveness of the braking system improves markedly when the brake fluid is changed.  After eighteen to twenty-four months, the brake fluid has absorbed a significant level of moisture from the air, braking performance becomes less effective and the brake peddle starts to feel noticeably spongy underfoot.  Before I changed my brake fluid one time, I had noticed that the brake peddle had started to feel spongy.  A couple of days after I changed it, I needed to brake suddenly when another vehicle made a right-hand turn across my path.  With the assistance of flicking the automatic transmission from ĎDriveí into ĎNeutralí, my vehicle pulled up to a standstill unusually quickly and stopped short of colliding with the other vehicle.  If there had still been old brake fluid in the braking system, as opposed to new fluid, Iím absolutely certain that the spongy braking would have resulted in me colliding with the other vehicle.

For all of these reasons and because the cost of changing brake fluid is quite low, itís highly recommend that you replace the brake fluid every twelve months.


Inspect the braking system every twelve months, including brake pad thicknessÖ

Every twelve months, inspect the thickness of all of the brake pads and/or brake shoes, as well as the condition of all of the flexible brake hoses and metal brake lines by cracking the wheel nuts, jacking the entire vehicle up, supporting it on axle stands and removing the wheels.

For more information on inspecting the braking system, please see the section titled, Inspecting the Braking System.


Use a proper double or single-filter dust mask to avoid breathing brake dustÖ

Whenever working on the braking system in such a way as to be exposed to brake dust (eg. replacing brake pads or brake shoes), it is ABSOLUTELY CRITICAL that you use a proper double or single-filter dust mask to minimise your exposure to breathing in the tiny, fibrous brake dust particles.  Because this dust can be very hazardous to your health in the long term, itís sensible to minimise your exposure to it when working on the braking system by avoiding breathing it in wherever possible.


Use brake cleaner to remove brake dust from the braking systemÖ

Brake dust can be safely cleaned off of braking system parts by spraying the parts with purpose-made brake cleaner available from your local automotive parts shop and letting the brake cleaner drain into a drip pan (positioned underneath the parts being cleaned) to carry the brake dust with it.  The brake parts can then be hosed down with water to remove any remaining traces of brake dust.  NEVER stir up the brake dust by blowing it away with compressed air and definitely do NOT stir it up by brushing it off with some kind of brush.


Donít use any hydrocarbon-based solvents to clean the braking systemÖ

NEVER use any hydrocarbon-based solvent such as kerosene to clean brake dust off of any brake parts because the safety and performance of the braking system can easily be impeded if the brake pads and/or brake shoes are contaminated by the hydrocarbon-based solvent.


Replace the brake disc rotors when you replace the brake padsÖ

Replace the disc brake rotors, or have them machined to restore trueness, when you replace the disc brake pads in order to ensure optimal braking performance.  Disc brake rotors are generally inexpensive enough these days to warrant total replacement rather than having them machined to restore trueness.  If replacement rotors are prohibitively expensive, ensure that the rotors are machined when the brake pads are replaced.

Some companies like Bendix produce brake pads that do away with the need to Ďbed iní the combination of new rotors and new brake pads by driving more sedately and avoiding excessive or high-speed braking for 200-300 kilometres (120-180 miles).  Your local automotive parts shop will be able to give you more information on these pads, as will the Bendix website.


Replace the disc brake pads and the disc brake rotors in left and right pairs...

Itís very important to replace the disc brake pads or the disc brake rotors on both of the left and right front wheels together or on both of the left and right rear wheels together.  Replacing the pads or rotor on only one wheel on one side of the vehicle while leaving the other old pads or old rotor on the other wheel on the other side of the vehicle can impede the handling and safety of the vehicle when braking.  This same principle also applies to replacing the brake shoes on both of the left and right wheels in the case of drum brakes, when the brake shoes on one of the wheels are found to be worn down past the minimum required thickness of friction material.


Have a qualified mechanic check over the braking system on your vehicle every twelve monthsÖ

The braking system on your vehicle makes a critically important contribution to the safety of your vehicle.  Itís therefore very important to have a qualified mechanic who has expertise in this area to check over your braking system every twelve months for proper functioning and safety.



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Copyright 2016 Andrew Mackinnon.  All rights reserved.