How to Bleed Brakes: Two-Person, One-Person and Vacuum Methods
Quick answer: Fill the master cylinder with fresh fluid of the right type. Starting at the wheel farthest from the master cylinder (usually right rear), put a clear hose on the bleeder screw into a bottle, have a helper press and hold the brake pedal, open the bleeder a quarter turn, close it before the pedal is released, and repeat until fluid comes out with no bubbles. Work toward the closest wheel, keep the reservoir topped up the whole time, and finish with a firm pedal.
When you need to bleed the brakes
- After replacing a caliper, wheel cylinder, brake hose, line or master cylinder
- When the pedal feels soft or spongy
- As part of a brake fluid change, which many makers recommend every 2 to 3 years
- If the reservoir ran low enough to let air in
What you need
- Fresh brake fluid of the type printed on your reservoir cap (DOT 3, DOT 4 or DOT 5.1; never mix in DOT 5 silicone fluid unless the system is built for it)
- A box-end wrench that fits the bleeder screws
- Clear tubing that fits snugly over the bleeder, and a catch bottle
- Jack and jack stands, and wheel chocks
- A helper, or a one-person bleeder or vacuum pump
- Rags and water: brake fluid damages paint
Brake bleeding order
Most cars bleed from the wheel farthest from the master cylinder to the closest: right rear, left rear, right front, left front. Some vehicles, including many with ABS or diagonal brake circuits, use a different order, so check the service information for your model.
Two-person method (pump and hold)
- Raise and support the car safely and remove the wheels if that gives better access.
- Top up the master cylinder with fresh fluid and leave the cap loosely on.
- At the first wheel, fit the hose to the bleeder and put the other end in the bottle with a little fluid in the bottom.
- The helper presses the pedal a few times and then holds it down firmly.
- Open the bleeder about a quarter turn. Fluid and air flow out and the pedal sinks.
- Close the bleeder before the helper lets the pedal up.
- Repeat until the fluid in the hose is clear with no bubbles, then move to the next wheel.
- Check the reservoir every few pumps. If it runs dry you will pull air back in and have to start over.
One-person and vacuum bleeding
One-person bleeder: a hose with a check valve lets you open the bleeder, pump the pedal yourself and close the bleeder when the fluid runs clear. Vacuum bleeder: a hand or air-powered pump pulls fluid through the open bleeder. Wrap the bleeder threads with plumber's tape so the vacuum does not draw air past the threads and make it look like there are bubbles. Gravity bleeding (open the bleeder and let fluid drip) works on some systems but is slow.
ABS cars and new master cylinders
Most ABS cars bleed normally as long as air has not reached the ABS unit. If the reservoir ran dry or the ABS unit was replaced, many models need a scan tool to cycle the ABS pump during bleeding. A new master cylinder should be bench bled before fitting.
How to know the air is out
- Fluid in the clear hose has no bubbles at every wheel
- The pedal is firm and high, and does not sink when held
- The pedal feels the same after the engine is started
If the pedal is still soft, re-bleed, check for leaks, and inspect hoses, calipers and the master cylinder.
Related parts
Shop brake pads, brake rotors, brake calipers and brake master cylinders by make, model and year, or browse all brake parts.
Questions
What order do you bleed brakes in?
Usually farthest from the master cylinder to closest: right rear, left rear, right front, left front. Some ABS and diagonal-split systems differ, so check your model's service information.
Can you bleed brakes by yourself?
Yes, with a one-person bleeder hose that has a check valve, or a vacuum bleeder.
How much brake fluid do I need to bleed brakes?
A simple bleed often uses less than a liter, and a full flush around 1 liter on many cars. Buy a little extra and use a sealed, fresh bottle.
Why is my brake pedal still soft after bleeding?
Usually air is still in the system, often from letting the reservoir run low or opening the bleeder while the pedal was released. Leaks, a failing master cylinder or swollen hoses can also cause a soft pedal.
