GM 19420798
Master Cylinder

The Brake Master Cylinder replacement process for a two-mode hybrid vehicle requires you to turn off the ignition without stopping at accessory mode and wait 1 to 3 minutes while avoiding brake pedal use to let the brake modulator and hpa bleed pressure. When enough time has passed you should take brake fluid from the Brake Master Cylinder reservoir and place it in a permitted container. Unplug the Brake Fluid Level Sensor connector and easily detach the Brake Master Cylinder reservoir by disconnecting both return and supply hoses. Separate the primary brake pipe from the system by capping it while plugging the master cylinder outlet. Repeating this process, disconnect all brake brake pipe fittings on the left and right side including the front fittings. Then detach the Brake Master Cylinder by discarding and installing the new parts. Take off the Brake Master Cylinder nuts and throw them away. Afterwards pull out both the Brake Master Cylinder and master cylinder seal. Bleed the master cylinder before you put the master cylinder seal and master cylinder onto the adapter while making sure the seal bottoms out. Use 2 new Brake Master Cylinder nuts to fasten the unit at 33 nm (24 lb ft). Use a torque wrench to secure the left and right front brake pipe fittings, right supply brake pipe fitting, left supply brake pipe fitting, and primary brake pipe fitting to 30 nm (22 lb ft). Fasten back the Brake Master Cylinder reservoir return hose quick connect and supply hose quick connect accessory. Then secure the Brake Fluid Level Sensor electric plug. Add brake fluid to the master cylinder tank then perform a brake system hydraulic bleeding process.

Before replacing the Brake Master Cylinder (JD9) or two-mode hybrid master cylinder you must turn the ignition off and leave it there without depressing the brake pedal. Then take out the brake fluid from the reservoir and place it in authorized storage. Unplug the brake fluid sensor electrical connection and separate both ends of the Brake Master Cylinder hose assembly. Position them on the side. To avoid fluid leaks tap the brake pipe primary fitting before sealing it with covers while also sealing the master cylinder outlet port. Repeat this process by disconnecting the left supply brake pipe fitting , right supply brake pipe fitting , right front brake pipe fitting , and left front brake pipe fitting , each with corresponding covers and seals. Seize off the Brake Master Cylinder nuts and remove them before pulling out the Brake Master Cylinder along with its master cylinder seal. To install the cylinder slide the Brake Master Cylinder seal onto its adapter first before placing the assembly with a properly seated seal onto the adapter. Use new master cylinder nuts and secure them to 33 nm (24 lb ft) torque setting. Fix the assembled brake connections between left front, right front, right supply, left supply, and primary brake lines with a torque of 30 nm. Join the Brake Master Cylinder reservoir return hose quick connect back to the supply hose quick connect then attach the Brake Fluid Level Sensor electrical connector. Put fluid in the Brake Master Cylinder reservoir then remove air from the hydraulic brake system.

The Brake Master Cylinder replacement process for a two-mode hybrid vehicle requires you to turn off the ignition without stopping at accessory mode and wait 1 to 3 minutes while avoiding brake pedal use to let the brake modulator and hpa bleed pressure. When enough time has passed you should take brake fluid from the Brake Master Cylinder reservoir and place it in a permitted container. Unplug the Brake Fluid Level Sensor connector and easily detach the Brake Master Cylinder reservoir by disconnecting both return and supply hoses. Separate the primary brake pipe from the system by capping it while plugging the master cylinder outlet. Repeating this process, disconnect all brake brake pipe fittings on the left and right side including the front fittings. Then detach the Brake Master Cylinder by discarding and installing the new parts. Take off the Brake Master Cylinder nuts and throw them away. Afterwards pull out both the Brake Master Cylinder and master cylinder seal. Bleed the master cylinder before you put the master cylinder seal and master cylinder onto the adapter while making sure the seal bottoms out. Use 2 new Brake Master Cylinder nuts to fasten the unit at 33 nm (24 lb ft). Use a torque wrench to secure the left and right front brake pipe fittings, right supply brake pipe fitting, left supply brake pipe fitting, and primary brake pipe fitting to 30 nm (22 lb ft). Fasten back the Brake Master Cylinder reservoir return hose quick connect and supply hose quick connect accessory. Then secure the Brake Fluid Level Sensor electric plug. Add brake fluid to the master cylinder tank then perform a brake system hydraulic bleeding process.

Bench bleed the master cylinder, then install the brake master cylinder seal ensuring it is fully seated, followed by the master cylinder to the adapter.