Chrysler 4485301 Master Cylinder Asm Brake Co

Bench bleeding the master cylinder is important to expedite the bleeding of the entire hydraulic system after installation. To bench bleed, insert threaded plugs into the cylinder outlet holes, fill both reservoirs with brake fluid, and support the master cylinder level to prevent spillage. Loosen and tighten one plug at a time while pushing the piston assembly into the bore to expel air, preventing its return. Alternatively, you can remove the plug, depress the piston, and use your finger to seal the hole to prevent air from re-entering. Repeat this for both ports, stroking the piston three or four times for each outlet to ensure complete air removal. Refill the master cylinder reservoirs and install the cover assembly, being mindful not to overfill them.

When replacing the master cylinder, position a container and layers of newspaper underneath it to catch any spilled brake fluid. Proceed to unscrew the steel line flare nuts, remove the lines, and cap them. Allow the fluid in the master cylinder to drain into the container. Then, remove the mounting nuts and detach the master cylinder from the booster. If a new master cylinder is being installed, it may be necessary to transfer the plastic fluid reservoir.