How to Install BMW E28 Brake Lines

1. Park the BMW on a flat, level surface. Loosen the lug bolts on all four wheels. Lift the car with a floor jack, one side at a time, and lower it securely onto jack stands on all four corners. Finish removing the wheels and set them aside.
2. Clean all of the brake components, including the brake caliper, rotor and brake line, with brake cleaner so that they are free of dirt and debris. Avoid getting any dirt or particles in the brake line when the old lines are removed.
3. Loosen the brake hose fitting where it threads into the caliper. Locate the two large bolts on the back of the caliper that hold the caliper to the suspension. Loosen and remove these bolts. Disconnect the brake pad wear sensor line near where it goes into the caliper if the vehicle is equipped with one. Slide the caliper off of the rotor.
4. Remove the brake line from the caliper by spinning the caliper until the hose unthreads from the brake line. Set the caliper aside. Loosen the fitting on the opposite side of the brake line with the wrench and then unthread it by hand. Wipe up any spilled brake fluid with a rag.
5. Attach the new brake line on the end opposite of the brake caliper first. Tighten the fitting on the end of the line with a wrench. Thread the opposite end of the line into the brake caliper by hand, ensuring that the threads do not become cross-threaded. Repeat the above steps for the remaining corners of the BMW.
6. Slide the caliper over the rotor. Install and tighten the caliper bolts. Finish tightening both ends of the brake line. Dispose of the excess brake fluid and rags according to the hazardous waste rules in effect in your community.
7. Remove the lid for the brake cylinder reservoir, located on the driver's side of the engine bay. Fill the master cylinder with fresh brake fluid to replace the fluid lost when the brake lines were removed.
8. Bleed the brakes with your preferred method. To bleed the brakes, attach a clear rubber line to the bleeder valve on the brake caliper. Place the opposite end of the line into a container filled with brake fluid. Loosen the bleeder valve and have someone pump the brake pedal until there are no air bubbles in the brake fluid. Tighten the bleeder valve and repeat for the remaining corners of the car.
9. Reinstall the wheels on the same corner they were removed from. Lower the car to the ground. Tighten the lug nuts. Carefully test drive the car to make sure the brakes are functioning correctly. The brake pedal should feel firm and the car should come to a stop quickly and safely.