HYDRAULIC BRAKING SYSTEM - Bleed air

Operation 3330A14 · Hydraulic brake system tests and checks

The air in the hydraulic circuit acts as a bearing, absorbing a large part of the pressure exerted by the brake pump and reducing the efficiency of the braking. The air is felt in terms of the "spongey" sensation at the brake pedal and the reduction in the braking capacity.

Place the car on a lift.

Refer to op. 3330A10 BRAKE FLUID - Check level and top up, if necessary.

Carry out op. 4450B12 front or rear wheels (two) - r+r

Carry out op. 4450B13 rear wheels(2) r r

Fill the brake fluid reservoir to the maximum level and tighten the cap.

1. Remove the protective cover for the bleed screw for one of the brake brake calipers.

2. Fit a transparent plastic pipe on the bleed screw.

3. Inser the other end of the pipe in a container of brake fluid.

Press and release the brake pedal several times very quickly and then keep it fully depressed.

Undo the bleed screw by 1/4 of a turn.

When the brake pedal reaches the end of travel position, tighten the bleed screw.

Press the brake pedal repeatedly and then keep it fully depressed.

Undo the bleed screw again by 1/4 of a turn.

Repeat the operation until the fluid flowing into the container is completely free of air.

During the bleeding, fill the brake fluid reservoir, as necessary.

Tighten the bleed screw.

Remove the pipe from the bleed screw.

Fit the protective cap on the bleed screw.

Repeat the operation for the other front brake caliper.

The brake fluid recovered should not be reused. The level should always be topped up with new fluid.

Bleed the air from the rear drum brakes.

Remove the protective cap from the bleed screw for one of the rear drum brake cylinders.

1. Fit a transparent plastic pipe on the bleed screw.

2. Insert the other end of the pipe into a container of brake fluid.

Press and release the brake pedal several times very quickly and then keep it fully depressed.

Undo the bleed screw by 1/4 of a turn.

When the brake pedal reaches the end of travel position, tighten the bleed screw.

Press the brake pedal repeatedly and then keep it fully depressed.

Undo the bleed screw again by 1/4 of a turn.

Repeat the operation until the fluid flowing into the container is completely free of air.

During the bleeding, refill the brake fluid reservoir, as necessary.

Tighten the bleed screw.

Remove the pipe from the bleed screw.

Fit the protective cap on the bleed screw.

Repeat the operation for the other rear drum brake.

If, after having carried out the bleeding operation, the system is not fully operational, repeat the entire procedure after having waited several hours for the brake fluid to settle down in the system.