The flexible hose at each corner is the part that fails first, because it flexes with suspension travel and perishes from the inside out.
A hose that has collapsed internally acts like a one-way valve: the brake applies but does not release, and the wheel drags and overheats. This is often misdiagnosed as a stuck caliper, so check the hose before replacing the caliper.
Rigid lines are sold as pre-bent sections, as straight lengths to be flared on site, and as coil. Listings state the length, the diameter, the fitting type and whether the line is coated against corrosion.
When replacing a hose, replace both sides of the axle if they were fitted at the same time originally. The second one is the same age and the same condition.
