Bench bleeding removes the air from the master cylinder prior to the installation
of the master cylinder. Bench bleeding reduces the amount of bleeding needed after
the installation of the master cylinder onto the vehicle.
- Plug the outlet ports.
- Mount the master cylinder in a vise with the front end tilted
slightly down.
- Fill the reservoir with clean DOT 3 brake fluid.
- Stroke the primary piston about 25 mm (1 in) several times
using a smooth, rounded end tool. Resistance to the primary piston travel will not
allow the full 25 mm (1 in) stroke when air is bled from the master
cylinder.
- Reposition the master cylinder in the vise with the front end tilted slightly
up.
- Repeat the stroke to the primary piston of about 25 mm (1 in)
several times.
- Reposition the master cylinder in the vise to the level position.
- Loosen the plugs one at a time.
- Push the piston into the bore in order to force the air from the cylinder.
- Tighten the plug(s) before the piston returns to the original position
in order to prevent air from being sucked into the cylinder.
- Fill the reservoir.
- Perform the normal bleeding procedure after the master cylinder is installed.