Whenever the vehicle is raised and supported securely on jackstands, inspect the rubber hoses connecting the steel brake lines with the front and rear brake assemblies for cracks, chafing, leaks, blisters, and other damage, as these are crucial components of the brake system. A light and mirror can aid in a thorough check, and any hose showing signs of wear should be replaced immediately. To replace a flexible hose, clean all dirt from the hose fittings, then use a flare-nut wrench to disconnect the metal brake line from the hose fitting, taking care not to bend the line. If the threaded fitting is corroded, apply penetrating oil and allow it to soak before attempting to loosen it. Disconnect the brake hose from the frame or bracket by removing the mounting fastener, and plug the metal line to prevent leakage. Unscrew the banjo bolt at the caliper to remove the hose, discarding the sealing washers. Attach the new brake hose to the caliper using new sealing washers and tighten the banjo bolt to the specified torque. Route the hose fitting into the frame or bracket as the original and secure it with the mounting fastener, then thread the metal line to the hose and tighten the fitting nut securely. Ensure that suspension or steering components do not contact the hose by having an assistant push down on the vehicle while observing for interference, and if replacing a front hose, check that it does not interfere with the steering linkage or knuckle during lock-to-lock turns. After installation, bleed the brakes, check the master cylinder fluid level, and add fluid as necessary, then carefully test brake operation before returning the vehicle to normal service. When replacing metal brake lines, use the correct parts, avoiding copper tubing, and purchase steel brake lines from a dealer or auto parts store. Prefabricated brake lines with flared ends and installed fittings are available, and if bending is necessary, use a tubing bender to prevent kinking. Ensure the new line is well supported in brackets with adequate clearance from moving or hot components, and tighten the fittings securely. After installation, check the master cylinder fluid level, add fluid as needed, bleed the brakes, and test brake operation before resuming normal use.
