Friday, October 15, 2010 02:44
Brake bleeding is one of the easiest, cheapest, and effective forms of preventive maintenance for the do-it-yourselfer. Done every two years, completely renewing brake fluid will not only help ensure maximum stopping power but also will extend the life of internal brake components. Another advantage: Like drawing blood from a human, brake bleeding will indicate the health of the brakes system.
I learned the value of regular brake bleeding when I was racing and encountered badly fading brakes: Blasting into a 65-mph turn at 130 with ineffective brakes is not nearly as much fun it sounds. I was baffled as the brake pads and rotors had been freshly serviced. In desperation, I bled the brakes. Out squirted a dark, bubbly mess reminiscent of cola syrup with a bit of carbonated water. Racetrack braking had raised the temperature of the brake fluid to nearly 300 degrees. This caused the brake fluid to break down and release vapors. Also, the moisture that brake fluid inevitably sucks out of the air boiled and added more air pockets, so the system wasn’t fully pressing the brake pads against the rotors. Bleeding the brakes before every on-track session became a ritual.
The moisture brake fluid naturally pulls out of the air not only reduces emergency stopping power but also encourages corrosion of internal brake parts. This corrosion tears rubber seals and ruins the expensive parts inside anti-lock braking systems. Another benefit of bleeding brakes: If the old brake fluid contains bits of rubber and other flotsam, you’ll know a complete brake job is required. If you’re considering buying a used car or have just acquired one, looking at the brake fluid will tell you a) how well the car was maintained and b) how soon you’ll need a brake job.
If you burn through brakes in a couple of years, you don’t need to bleed your brakes. I have a 10-year-old Toyota 4Runner on its third set of front pads and second set of rear shoes. I’m convinced that bleeding the brakes every two years meant that the calipers and drums didn’t need rebuilding. (It’s far more expensive to rebuild calipers than just slap in a new set of pads and machine the drums.) I also have a 2003 Camry and an 2000 Ranger. We regularly bleed their brakes.
Over the years, several professional mechanics have told me that it wasn’t necessary to bleed brakes. None gave a good-enough-for-me reason. None could debate my points. Told one mechanic who said I didn’t need my brakes bled, “Okay, I know I don’t NEED them bled, but I WANT them bled. And I’ll pay you.” He still wouldn’t do it. My guess is that they made the assessment that bleeding the brakes wouldn’t produce the results I desired. I could be wrong. I often am.
In Part 2 of this series we’ll tell you HOW to bleed brakes.