Check metal brake lines and rubber brake hoses frequently for leaks and external damage. Metal lines are prone to crushing and kinking under the vehicle. Any such deformation will restrict the proper flow of fluid and therefore impair braking at the wheels. Rubber hoses should be checked for cracking or scuffs; such damage can compromise the hose and fail under pressure.
Before disconnecting any lines, ensure that the connection is completely clean. Use a stiff bristle brush and non-chlorinated brake cleaner), and be sure to plug the lines and ports as soon as they are opened. Flush all new lines and hoses with brake fluid before installation to remove any contamination.