Looking for ways to save money on car maintenance? Not enough time to take your car in to the mechanic prior to every track day? Then bleed your brakes by yourself!
Track day drivers love robust brakes, maybe even more than horsepower…. After tires, brake system operation is the next preparation priority. All that horsepower must be absorbed and dissipated at the end of every straight (see this related post on brakes), inspecting and maintaining proper brake system operation is on your checklist prior to every drivers school track event or competitive race. If you are comfortable spinning wrenches to change spark plugs, bleeding brakes is hardly more challenging, so D.I.Y!
Brake fluid that is old has absorbed moisture from the atmosphere, brake fluid that has been exposed to high temperatures may have air in the calipers, either way you should bleed brakes prior to a day or weekend at the track to dramatically reduce the possibility of missing track time due to brake problems.
How do I do it? Here’s my method that’s worked on 90% of cars I’ve owned or worked on in the last couple decades, from Civics to F40’s:
WHAT YOU NEED
- Brake fluid, three – four 12oz cans
- Two containers to collect old fluid from calipers (bleed bottle), old plastic water bottles will work fine
- 3/16” vinyl tubing, two 12” long pieces
- Two tie-wraps
- Wire to hang bleed bottles from caliper/ rotor
- Two closed-end wrenches (probably 11mm)
- Tools to raise and support car, remove wheels
- Shop towel
Here are the abbreviated steps (we’ll expand on some steps later):
- Raise and support entire car, remove wheels
- Clean area around master cylinder, wrap shop towel around cap area for potential spills, remove cap
- Hang bleed bottle near one front and one rear caliper so bottle is higher than bleed screw
- Place wrench (may be 11mm) on bleed screws so opening screw 1/2 to 3/4 turn is possible without obstruction
- Place tubing on bleed screw nipples
- Open bleed screws, both on the front and rear caliper (I usually do driver side first)
- Ensure tubing rises higher than bleed screw (this is vital)
- Observe fluid rising in tubing (without depressing brake pedal), you may see some air bubbles
- Slowly depress brake pedal, slowly release brake pedal; inspect bleed bottles for air or dirty fluid coming out of calipers
- Cycle pedal about five times, always pushing and releasing slowly
- Check master cylinder fluid level
- When you’ve removed about a full can’s worth of fluid (12oz), close bleeders and move to other side of car
- Repeat steps to bleed the other two calipers
- After closing all bleed screws (torque to approximately 9 ft-lb, DO NOT OVERTORQUE), depress brake pedal a few times to check operation
Q Don’t I have to close the bleed screw each cycle of the brake pedal?
A No, not for most cars; observe the fluid as someone else works the brake pedal, notice that the fluid does cycle up/ down, but fluid always remains in the bleed tubing. More fluid is coming out on the brake pedal down stroke vs. sucking back into the caliper on the brake pedal release stroke; this is why the tubing and waste fluid bottle must remain higher than the caliper bleed screw.
Q I’ve read to do one caliper at a time.
A You can if you want, no harm done. I’m saving time by cycling one front and one rear simultaneously. All modern cars have separate chambers in the master for front and rear calipers so bleeding one front with one rear is perfectly fine.
Q So can I do this process without a helper pushing the brake pedal?
A Yes, that’s the beauty of this method.
Q How do I know if my car won’t work with this method?
A When the fluid is consistently sucking all the way back into the caliper on each brake pedal release. When this happens you have no choice but to find a helper to press the pedal; then, open bleeder, yell “down” and helper depresses pedal slowly, helper says “down” when it’s to the floor, you close bleeder, yell “up”, helper releases slowly, says “up”, then repeat…
Q Why “slowly” depress and release brake pedal?
A So fluid in the caliper and lines does not move so fast as to cavitate and induce air into the system.
Q What fluid do you recommend?
A That’s an article in itself; suffice to say I’m currently using Ford’s High Performance Brake Fluid which is the factory fill on my 2010 Mustang GT, is manufactured by Dow Corning and has a dry boiling point of 500°F and have zero fluid issues as long as I take a mile or so for cool down during our Hooked On Driving drivers school events.
Q My car’s ten years old and never had the brakes bled, what should I be concerned with?
A Corrosion; bleed screws are likely corroded to the caliper, experienced technicians keep an acetylene torch handy when maintaining brake systems on older cars. Propane doesn’t cut it (burns too cool), maybe PB Blaster will but only after many days treatment. If you have any concern that bleed screws are corroded it’s time to take your car to a professional.
Make your own bleeder bottles
- Drill a hole in the cap just large enough for the vinyl tubing to pass through
- Cut tubing to size (perhaps 12 inches)
- Place tie-wrap on one end of tubing, this acts as a stop to prevent tubing from falling out
- Screw cap back on
- Fashion a lanyard, I use safety wire (0.032”) and safety wire pliers
That’s it, easy right?
You have questions, we have answers; post questions below.
Yes, there are MANY more methods, if you’re experienced with a different method then by all means use yours. Finally, for street legal vehicles always follow your manufacturer’s recommended methods and products!