Recently I told you why it’s good to periodically bleed your brakes (Bleeding Brakes: Easy, Effective Preventive Maintenance). Now, I’m going to tell you how to do it. Here’s what you need to bleed brakes:
- Two or three small bottles of brake fluid. (Don’t buy the large containers: Once brake fluid is opened, it must be used or taken to the recycler.)
- Someone to help you who will precisely follow directions. (A love interest is not a great choice, while using a spouse is a just asking for a long-running argument.)
- Jack, tools to remove wheels, at least one real jackstand, and something to use as wheel chocks.
- Combination box-end/open-end wrench that fits the nipple on the brake caliper or brake drum.
- Length of clear plastic hose that fits tightly over the brake nipple.
- Safety glasses because the hose will inevitably pop off and fluid will spray everywhere.
- Clear plastic container.
- Container to collect used fluid and take it to the recycler.
- Rags, paper towels, and kitty litter to clean up the inevitable mess.
- Can of brake parts cleaner to clean spilled fluid from rotors or calipers.
- Beer or a dinner reservation to pay your helper. (If you pay with beer, demand work first.)
Step 1: Chock one or both front tires and the left rear with bricks or wood blocks so the car can’t slip off the jack. Engage the parking brake. Make sure the car is in Park or, on manuals, either Reverse (if the car is pointed downhill) or First (if pointed uphill).
Step 2: Jack up the right rear of the car, remove the right rear wheel and set the car down the jackstand. (If you have four jackstands, at this point you can remove all four wheels.)
Step 3: Make sure the master cylinder reservoir, found in the engine compartment, is full. Repeat this check regularly: Running the master cylinder dry is bad.
Step 4: Find the bleeder valve. It looks like a nipple and should be covered by rubber thingie that looks like a ball cut in half. Remove the cover. It will then lose itself to you. Cats carry them away, I think.
Step 5: Slip the box-end portion (the part that makes a complete circle) of the wrench over the nipple. Slide the plastic tube over the nipple and run it into the clear plastic container. Clear tubes and containers allow you to inspect the exiting brake fluid.
Step 6: Tell your assistant to smoothly press down on the brake pedal and hold it down. Emphasize smoothly: Aggressive pumping will turn large air pockets into difficult-to-remove tiny bubbles. (If you suspect there’s a lot of air in the system, have the assistant smoothly press and release the pedal two or three times before holding it down.) When assistant is firmly holding the pedal down, have him shout “Down” and—this is important—keep firm pressure on the brake pedal as it moves toward the floor.
Step 7: Open the bleeder valve by turning it about a quarter to a half turn counter-clockwise. You’ll know when the valve is open far enough when brake fluid squirts out. After no more than one second, immediately tighten the nipple. Inspect the fluid that comes out. (If the fluid is black and chunky, take the car to a pro.)
Step 8: When the valve is closed tight, shout “Up.” The assistant should smoothly release the pedal and respond “Up.” (Sooner or later, even the best helper will be “up” when they should have been “down.” It’s not disastrous: You’ll just have to do a bit more bleeding.)
Step 9: Again shout “Down.” When the assistant responds “Down,” open the valve as in Step 7. Then retighten the valve and shout “Up.” Your assistant must respond “Up.”
Step 10: Replenish fluid in the master cylinder reservoir.
Step 11: Repeat Steps 6 through 10 until you believe fresh fluid has reached that wheel AND the fluid runs clear and free of bubbles. If bits of rubber or flotsam flows out, a major rebuild is in your near future. Do not over tighten the bleeder. Replace the rubber bootie if you can find it. (You can’t. Go buy a new one.)
Now you’ve bled one wheel. Only got three more to go. Do the left rear next. Then the right front and finish with the left front. Front brakes provide about three-quarters of stopping power, so you want to ensure they have completely fresh fluid.
After you’ve bled all four wheels, have your assistant press the brake pedal while you look for leaks. The brake pedal should be firm. If it mushes toward the floor, either you did something wrong (like under- or over-tightening a bleed valve) or you’ve got another problem.
One more note about bleeding: If you have a manual transmission, both the clutch master cylinder and slave cylinder need regular bleeding, too.