Front brake bleeding, when air enters hydraulic brake circuit, is the only option to recover its use, when the action on the brake lever is not transmitted by the pressure to the pads on the disc. Air tends to enter due to a low level brake fluid in the pump reservoir, together with some tumble or actuation of the lever with the motorcycle dropped. In addition, as the brake pads wear, the pistons that push them move towards the disc and brake and fluid level drops. This air in the circuit is generally at the top, next to the brake master cylinder piston. If so, to proceed with front brake bleeding it is easy with the following steps:
- Put the motorcycle resting on its leg, with the wheel straight. Take a large screwdriver and carefully insert it between the pads and the disc. By turning the screwdriver, the brake pads are opened, pushing the brake caliper pistons in and pushing the brake fluid into the reservoir. This can be done without removing the wheel.
- Remove the cap from the brake fluid reservoir and check that the level is at least half. If not, fill up with brake fluid. Operate the brake lever repeatedly, observing that it builds up pressure as air bubbles come out of the lower part of the tank, without the tank falling below average level. If it does not pick up pressure, the brake pads will have to be separated further.
- Once the brake circuit pressure and its functionality have been restored, adjust the fluid level. EYE! the brake fluid is quite corrosive so it must be cleaned well and not touched with your hands.