brakesBack in the days of drum brakes it used to be easy to tell when your brake system needed attention; the brake pedal had to be pressed harder for the same effect. Or it went all squishy. Or you had to pump the pedal to build up pressure. But in these days of four-wheel disc brakes as standard equipment all those handy hints are gone. When a mechanic tells you there’s still plenty of life left on your brake pads you tend to think everything’s fine.

What you’ve missed is that other vital ingredient in your braking system, the fluid.

Brake fluid is special stuff. Because brakes get really hot really fast it has to be able to work at very high temperatures, so its boiling point is high. Good brake fluid can operate at temperatures of up to 500 degrees C.

The downside is that it’s corrosive and when corrosion happens contaminants can get into the system. And anything that lowers the fluid’s boiling point, and hence its ability to handle high temperatures, has an adverse effect on braking.

Water is the big problem. Over both time and distance water that seeps into brake fluid condensates along the brake lines and in the master cylinder, the heart of the brake fluid’s circulation system interfering with proper performance.

So how do you know it’s happening? “Well, you don’t,” says Maurice Carmeni, of Hughes Automotive in Burwood. “Really the only way to tell is with an instrument that you dip into the fluid to measure the extent of contamination.”

He suggests the brake system should be entirely flushed out and filled with new brake fluid every two years or 30,000 km. This is not just a matter of adding new brake fluid, the entire system needs to be flushed to get rid of moisture and any other nasties. But car owners economise.

“Cars that should be serviced every six months are increasingly getting serviced every 12 months, cars that need it every 12 months are going out to 18 or 24,” he said. “And people assume that because their brake pads are okay the brakes don’t need servicing, so they tell their mechanic to let it go. They’re operating on a false sense of security.”

And here’s the thing – while inner city residents may not drive as far as folk who live on the outskirts or in the country they’re much harder on their brakes, and that’s because with inner-city traffic they’re on them all the time. Try counting the number of times you use the brake pedal between home and work.

“This is not just happening with older cars, it’s across the board,” Maurice says, and adds that cars with ABS brakes (which is most of them these days) are particularly susceptible.

Flushing the brakes usually takes about half to three quarters of an hour and adds around $90 to the service bill.

Published July 2015