How to bleed brakes
Bleeding removes air and old fluid from the brake system. Brake fluid absorbs moisture over time, and many manufacturers specify replacement every two years.
Tools
- Ring spanner for the bleed nipples
- Clear tube and a bottle
- Helper or one-person bleeder
- Jack and axle stands
Parts & materials
- Brake fluid of the specification on the reservoir cap (e.g. DOT 4) — never mix with DOT 5 silicone fluid
Step by step
- Check the manufacturer's bleeding sequence; commonly the wheel furthest from the master cylinder first. Cars with ABS may need a scan tool to cycle the ABS unit.
- Fill the reservoir with fresh fluid and keep it topped up throughout; letting it run dry lets air in.
- Fit the tube to the bleed nipple with the other end submerged in fluid in the bottle.
- Have a helper press and hold the pedal, open the nipple, close it, then release the pedal. Repeat until clean fluid without bubbles comes out.
- Repeat at each wheel in sequence.
- Tighten the nipples, top up to the MAX mark and check the pedal is firm before driving.
- Test the brakes at low speed somewhere safe.
Safety: Brake fluid damages paint: wipe spills immediately with water.
Safety: Brakes are safety-critical. If the pedal is not firm, do not drive.
Symptoms this can fix
Procedures differ between vehicles. Check your vehicle's service information for specifications, torque values and any special steps.