Is it time to flush your brake system?

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A regular part of routine car maintenance requires a brake flush at regular intervals, some say every 30,000 miles, or a time internal, such as every three years. If your brake fluid is dark brown, then chances are it needs to be flushed.

Why is this necessary? Brake fluid is hygroscopic, which means it can absorb moisture and dirt from the atmosphere. That is one reason why you should not leave the cap off your brake fluid resevoir for extended periods, as the fluid will suck up the moisture in the air. This will degrade the brake fluid's ability to resist high temperatures commonly encountered in every day driving.

Brakes are friction devices and as such generate a lot of heat. Brake fluid is really close to the action and is capable of resisting these temperatures and still do it's job. After a period of time the fluid absorbs water and dirt which degrades it's boiling point. A brake flush removes all this water and debris and restores brake fluid integrity.

Flushing the brakes can be done at most repair shops, and you can do it yourself if you are comfortable working on your own brakes. IF YOU MESS UP IT CAN BE SERIOUS! Also, brake fluid will take paint off most surfaces, it you spill it on your fender or wheels, clean it off with lots of water immediately. Getting your car repainted is quite expensive. When you're done, make sure you have a firm brake pedal before you drive it!

With that said, brakes can be easily flushed in your own garage, with little or no equipment. It entails jacking up the car and removing the wheels (Be sure to use jackstands, never use a jack alone.). Remove as much brake fluid as you can from the resevoir. A turkey baster can be used to suck out the fluid, and refill with clean fluid. Loosen the bleeder screws on top of the calipers or if you have drum brakes in the rear, the bleeder screw is close to the brake line. It's best to put a piece of clear hose on the bleeder and run it into a bucket to keep control of the mess. The initial fluid color is brown, so let it run out till it get's clear. As the fluid drains make sure you keep it topped up, if you let air into the brake system you'll have to let it bleed out, again. Also, gravity bleeding takes a while.

There are simple vaccum tools available to make this job easier and faster. A brake bleeder like Mityvac requires a compressed air source, so you'll need an air compressor in your garage (you need one anyway to keep tires filled up). With the compressor running you attach an air hose to the bleeder, then loosen the bleeder screw on the caliper and attach the vacuum hose to the bleeder. As it scavenges out the old brake fluid be sure to keep it topped up. When your done with a wheel, pull off the vacuum hose, but leave the bleeder open, till fluid runs out and there are no more bubbles (which only takes a few seconds). The vacuum brake bleeder contains all the fluid in it's own resevoir for disposal afterwords, leaving no mess.

Always use a good brand name brake fluid, like Castrol GTLMA, Brake flushes are not that expensive to be done by a repair shop. It's best to follow the maintenance schedule in your owners manual, but a good rule of thumb to go by is every three years.