GM 19209200
Master Cylinder

Begin Brake Master Cylinder maintenance by mounting the flange to a vise so you can access the primary Piston at its rear end. Install fittings with matching flare seats onto the master cylinder ports before placing them in clean reservoir solutions. Lead the transparent hoses to the master cylinder reservoir through fittings which match the required flare seat. Delco supreme 11(R) or gm p/n 12377967 (Canadian P/N 992667), or equivalent dot-3 brake fluid should be used to fill the reservoir to achieve a minimum halfway point while the hose ends should remain submerged under fluid. A round-shaped tool helps you push and pull the primary Piston with a 25mm (1 inch) journey depth multiple times to observe fluid movement from the ports. Air removal from the pistons causes the primary Piston to become harder to depress while its travel distance shortens. Climb through multiple pumping cycles to achieve fluid drainage without bubble formation through the ports. Follow these steps to remove the transparent hoses: replace the master cylinder reservoir cap and diaphragm while taking off the fittings with hoses from the ports then wrap the master cylinder in a clean shop cloth to avoid spills. The vise should release the master cylinder before the operation ends.

Attach the brake master cylinder reservoir to the master cylinder if it was removed, then bench bleed the master cylinder.

Remove the plugs from the brake pipes, install the brake pipes to the master cylinder, and tighten the fittings to 29 N.m (21 lb ft).

Bench bleed the master cylinder.