GM 18022002
Master Cylinder

After placing the Brake Master Cylinder mounting flange into the bench vise grab you should position it to access the rear side of the primary Piston. Put suitable hoses into the master cylinder ports through new fittings after removing its reservoir diaphragm and cap. Install transparent fluid lines onto these fittings before bringing them into the reservoir system. Place delco supreme ii®, gm p/n 12377967 (Canadian P/N 992667) brake fluid from a sealed container into the reservoir until it reaches the halfway mark while completely submerging the ports under the fluid. Depress the primary Piston several times using a rounded tool to 25mm depth while observing fluid flow from the ports. The increasing effort needed to push the Piston shows that air bleeding process is complete. Perform this operation until fluid flows easily from the ports without air bubbles appearing. Reinstall the master cylinder parts and take off fittings with hoses from ports while using cloth to catch any spills.

Place the Brake Master Cylinder mounting flange into the bench vise to fix it but allow access to the end of the main Piston when you need to repair the Brake Master Cylinder. Put suitable fittings with flare connection on both master cylinder ports to create hose connections. Also remove the existing parts from the reservoir and install them now. Route the clear hoses to the master cylinder through its fitting points. Place delco supreme 11 (R)(GM Part 12377967) or equivalent dot-3 brake fluid in the reservoir until it reaches at least halfway and make sure both ends of the hoses are immersed in fluid. Depress the primary Piston with a round-ended tool to bleed air from the system while monitoring fluid flow from the ports; as air leaves the pistons the effort needed will increase and Piston stroke decreases. Keep operating the tool to move the primary Piston until fluid exits without air bubble presence. Rewash the transparent hoses from the reservoir and reattach the master cylinder reservoir cap along with the diaphragm before taking off the fluid ports fittings. Keep the cylinder dry during all steps by covering it with a clean cloth as you remove it from the vise.

The first step when fixing the Brake Master Cylinder safety depends on your knowledge of brake fluid warnings and its impact on car paint and electrical equipment. Delco supreme ii brake fluid part number 12377967 (Canadian part number 992667) provides the best protection to internal rubber seals because it must be taken from a clean sealed container. Set the Brake Master Cylinder mounting flange in the vise to safely reach the rear of the main Piston for service work. Install proper attachments on the master cylinder ports and connect them to hose pipes before removing its reservoir components. Connect transparent hoses to these fittings then position the hoses into the reservoir space. Pour the suggested brake fluid into the reservoir until the liquid reaches half-way and the hose ends remain covered by fluid. Press and release the primary Piston 25 mm (1 inch) with a round-ended tool several times while checking fluid flow from the ports; the strength needed to push the Piston increases as air exits the brake system. Perform this action until the ports discharge liquid without trapped air. Unplug the transparent hoses from the reservoir and put them back in place before disconnecting the master cylinder fittings from their ports. Once done keep the master cylinder covered by a cloth during removal.

First step to replace the Brake Master Cylinder is disconnecting the Brake Fluid Level Sensor and the brake pipes from the master cylinder while installing rubber caps or plugs to seal the open brake pipe fittings to prevent brake fluid loss and contamination. Install brake pipe caps then loosten the master cylinder unit bolts to extract the master cylinder with complete drain of brake fluid. Before installation into the vacuum Brake Booster you should bench bleed the master cylinder then install and secure its mounting nuts to 25 nm (18 ft. Lbs.). Join the brake pipes to the master cylinder and fix the pipe connections at the master cylinder with 15 nm (11 ft. Lb) torque settings. Attach the electrical connection to the brake fluid sensor then perform brake system bleeding.

Fix the Brake Master Cylinder by first locking its mounting flange inside a vise tool to access the back of the primary Piston. Put suitable fittings inside the master cylinder ports by removing its cap and diaphragm to match required flare seats for attaching hoses. Connect transparent hoses to the fitting ends and position them into the master cylinder reservoir. Submerge the ends of both hoses into delco supreme 11 (R) brake fluid from its sealed container until the reservoir holds at least half its capacity. Depress the primary Piston several times with a smooth rolling tool to push fluid out the ports. As air leaves the pistons the pressure increases and its movement shrinks. Repeat your actions until brake fluid moves easily from both ports without any air in the lines. Place the master cylinder reservoir cap and diaphragm before you remove the transparent hoses and detach the fittings with the hoses from their ports. Then wrap the master cylinder with a clean shop cloth while preventing any spills. Take the master cylinder off the vise at the end.

The first step to replace the Brake Master Cylinder involves disconnecting the fluid sensor electric connector and brake pipes from the master cylinder while safely covering opened pipe ends with rubber plugs. Detach the two nuts keeping the master cylinder mounted and take out the master cylinder. When keeping the master cylinder for reuse take out the reservoir first. Put back the Brake Master Cylinder reservoir onto the master cylinder if needed then run a regular master cylinder procedure before putting it onto the vacuum Brake Booster. Tighten the two Brake Master Cylinder mounting nuts by turning them to a torque of 25 n.m (18 lb ft). Secure the brake pipes to the master cylinder and tighten them to 32 n.m (24 lb ft). You must now combine the electrical connector with the Brake Fluid Level Sensor while releasing brake system pressure.

Clamp the Brake Master Cylinder flange into a vise bench to reach the primary Piston from its rear side. After removing the cap and diaphragm from the master cylinder reservoir space add fitting parts to both ports for connecting the hoses. Connect the transparent hoses to these fittings and lead them into the reservoir space. Have both end parts of the hoses entirely inside a clean sealed container while pouring delco supreme 11(R) brake fluid (GM P/N 12377967 or its equal) into the reservoir up to its half point. Depress the primary Piston several times when using a smooth tool to observe fluid flow through the ports; as both pistons release air you will need more pressure to push down while Piston travel becomes shorter. Keep pumping the primary Piston until brake fluid flows easily through both ports without air bubbles included. Insert the reservoir cap and diaphragm then take out both fretting hoses from the brew ports following cloth wiping to defend against leaks.

Set the Brake Master Cylinder mounting flange in a workbench vise where you can easily reach the rear of the primary Piston. Insert suitable fittings on the master cylinder ports that match the required flare seat and let you attach hoses. Put clear tubing onto these hose fittings before letting them enter the master cylinder reservoir. Place delco supreme 11 brake fluid gm p/n 12377967 or oem equivalent from a sealed container into the reservoir until it reaches the midway mark with both hoses submerged. Press and release the primary Piston 25 mm (1 inch) deep several times with a smoothed tool while monitoring fluid flow out of the ports. The force needed to push down the primary Piston will grow while its movement distance shrinks because of decreasing air pressure. Let fluid run out of the ports until no air bubbles appear anymore. Repicture the transparent hoses from the reservoir then restore the master cylinder parts before removing the fittings with their hoses while keeping the cylinder covered by a clean cloth. Remove the master cylinder from its holding position after finishing.

Before working on the Brake Master Cylinder you need to disconnect its electrical connector and brake pipes from the master cylinder while also sealing brake pipe openings with rubber parts to avoid brake fluid loss and pollution. You start by plugging the opened brake pipe ends and unscrewing the master cylinder mounting nuts to take the cylinder out of the vehicle while draining all brake fluid from the reservoir. Bleed the master cylinder at the bench before connection to the Brake Booster. Tighten its mounting nuts to 29 n.m (21 lb ft). Plug the brake pipes first then attach them to the master cylinder with 32 n.m torque and connect the electrical plug to the Brake Fluid Level Sensor. Conclude the hydraulic brake system bleaching process.

Remove the plugs from the brake pipes and connect them to the master cylinder, tightening the brake pipe fittings at the master cylinder to 30 N.m (22 lb ft) if equipped with ABS, or to 27 N.m (20 lb ft) for the front brake fittings and 25 N.m (18 lb ft) for the rear fittings if not equipped with ABS.

Plug them and apply low pressure, non-lubricated, filtered air into the front outlet port to remove the secondary piston along with the primary and secondary seals and the return spring.

Secure the master cylinder with the 2 mounting nuts, tightening them to 25 Nm (18 ft. lbs.).

Reattach the master cylinder reservoir and its cap and diaphragm, then install the master cylinder back into the vehicle.

Plug the open brake pipe fitting ends, remove the 2 master cylinder mounting nuts, and take out the master cylinder.

Install the master cylinder to the vacuum brake booster, ensuring to tighten the 2 brake master cylinder mounting nuts to 25 Nm (18 ft. lbs.).

To prevent contamination.

Remove the master cylinder reservoir cap and diaphragm.

Secure the attaching nuts to 23 Nm (17 ft. lbs.) and reattach the brake pipes, tightening them to 33 Nm (24 ft. lbs.).

Remove the plugs from the brake pipes and connect them to the master cylinder.

Disconnect the electrical connector from the brake fluid level sensor and the brake pipe fittings from the master cylinder, capping the fittings and plugging the outlet ports to prevent fluid loss and contamination.

Fill the reservoir with new Delco Supreme II Brake Fluid GM P/N 12377967.

Remove it from the vehicle and secure the mounting flange in a bench vise, ensuring the rear of the primary piston is accessible.

Plug the open brake pipe fitting ends, remove the 2 master cylinder mounting nuts, and take out the master cylinder.

Attach the master cylinder to the vacuum brake booster and secure it with the two mounting nuts, tightening them to 25 N.m (18 lb ft).

Remove the plugs from the brake pipes, connect the brake pipes to the master cylinder, and tighten the fittings to 15 Nm (11 ft. lbs.).

Using a smooth, round-ended tool, depress and release the primary piston about 25 mm (1 inch) several times, observing fluid flow from the ports until fluid flows freely without air bubbles.

Clean the outside of the master cylinder reservoir around the cap.

Start by installing the master cylinder reservoir and bench bleeding the master cylinder before installation.

Disconnect the brake pipes from the master cylinder and the fluid level sensor electrical connector.

Drain all brake fluid from the master cylinder reservoir and remove the reservoir.

Remove it from the vehicle and secure the mounting flange in a bench vise, ensuring the rear of the primary piston is accessible.

Fill the master cylinder reservoir with brake fluid and bleed the brake system.

Install the master cylinder mounting nuts.

Install the master cylinder mounting nuts and tighten them to 29 N.m (21 lb ft).

Disconnect the electrical connector from the brake fluid level sensor and the brake pipes from the master cylinder.

Disconnect the electrical connector from the brake fluid level sensor and the brake pipes from the master cylinder, ensuring to install a rubber cap or plug on the exposed brake pipe fitting ends to prevent fluid loss and contamination.

Remove the transparent hoses from the reservoir, reinstall the master cylinder reservoir cap and diaphragm, and remove the fittings with the hoses from the ports.

Remove the reservoir from the master cylinder.

Inspect both the diaphragm and the reservoir cap for cuts, cracks, nicks, or deformation, and replace any affected components.

Inspect for cracks, scoring, pitting, or corrosion, and replace the master cylinder if any issues are found.

Continue until fluid flows freely from the ports without air bubbles.

Attach the brake master cylinder reservoir to the master cylinder if it was removed.

Fill it to the full level mark with Delco Supreme II Brake Fluid or equivalent DOT 3 brake fluid.

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

Remove the 2 master cylinder mounting nuts and take out the master cylinder. If reusing, remove the reservoir from the master cylinder.

Secure the mounting flange in a bench vise, ensuring the rear of the primary piston is accessible.

Remove the transparent hoses from the reservoir, reinstall the master cylinder reservoir cap and diaphragm, and then remove the fittings with the hoses from the ports.

Secure the mounting flange in a bench vise to access the rear of the primary piston.

Disconnect the electrical connector from the brake fluid level sensor and the brake pipes from the master cylinder, ensuring to install a rubber cap or plug on the exposed brake pipe fitting ends to prevent fluid loss and contamination.

Remove the master cylinder reservoir cap and diaphragm.

Plug them and apply low pressure, non-lubricated, filtered air into the front outlet port to remove the secondary piston along with the primary and secondary seals and the return spring.

Attach transparent hoses to the fittings and route them into the reservoir.

Connect the electrical connector to the brake fluid level sensor and bleed the hydraulic brake system.

Connect the hydraulic lines and install the tube nuts, tightening them to 15 Nm (11 ft. lbs.), then connect the rubber hose to the reservoir nozzle and secure it with a clamp.

Use a smooth, round-ended tool to depress the primary piston and install the new piston retainer, then reattach the master cylinder reservoir and its cap and diaphragm before finally installing the master cylinder back into the vehicle.

Remove it from the vehicle and secure the mounting flange in a bench vise, ensuring the primary piston is accessible.

Reconnect the electrical connector to the brake fluid level sensor and bleed the hydraulic brake system.

Remove the air inlet panel support bracket push nut from the master cylinder mounting stud, pull the bracket outward, and rotate it out of the way.

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

Remove the 2 master cylinder nuts and take out the master cylinder.

Install the 2 brake master cylinder mounting nuts and tighten them to 25 N.m (18 lb ft).

Disconnect the electrical connector from the brake fluid level sensor and the brake pipes from the master cylinder, ensuring to install a rubber cap or plug on the exposed brake pipe fitting ends to prevent fluid loss and contamination.

Install a rubber cap or plug on the exposed brake pipe fitting ends.

Disconnect the electrical connector from the brake fluid level sensor and the brake pipes from the master cylinder.

Lubricate the master cylinder bore, secondary piston, return spring, and all overhaul components with Delco Supreme II® or equivalent DOT-3 brake fluid from a clean, sealed container.

Install it to the vacuum brake booster and tighten the mounting nuts to 33 Nm (24 lb ft).

Bench bleed the master cylinder.

Begin by removing the master cylinder while ensuring not to disturb the screw retaining the primary spring to the secondary piston.

To prevent brake fluid loss and contamination.

Plug the open brake pipe ends, remove the master cylinder mounting nuts, and take the master cylinder out of the vehicle, draining all brake fluid from the reservoir.

Install a rubber cap or plug on the exposed brake pipe fitting ends.

Clean the outside of the master cylinder reservoir around the cap.

Clean the outside of the master cylinder reservoir around the cap.

Install the master cylinder to the vacuum brake booster, ensuring to tighten the brake master cylinder mounting nuts to 25 Nm (18 ft. lbs.).

Disconnect the electrical connector from the brake fluid level sensor and the brake pipes from the master cylinder.

Next, remove the master cylinder mounting nuts and take out the master cylinder.

Remove the plugs from the brake pipes and connect them to the master cylinder, tightening the fittings to 33 Nm (24 ft. lbs.).

Install a rubber cap or plug on the exposed brake pipe fitting ends.

Reconnect the electrical connector to the brake fluid level sensor and bleed the hydraulic brake system.

Connect the fluid level sensor electrical connector.

Secure the mounting flange in a bench vise to access the rear of the primary piston.

Use a smooth, round-ended tool to depress the primary piston and install the new piston retainer, then reattach the master cylinder reservoir and its cap and diaphragm before finally installing the master cylinder back into the vehicle.

Replace the master cylinder.

Clean with denatured alcohol and inspect for cracks, scoring, pitting, or corrosion.

Reconnect the electrical connector to the brake fluid level sensor and bleed the hydraulic brake system.