The flexible rubber brake hoses connect the hard lines to the moving calipers, and they wear out with age. A bad hose causes braking problems that can be tricky to diagnose. Here are the symptoms of a bad brake hose.
A dragging brake or pull
An old hose can break down internally and swell shut like a one-way valve - it lets pressure to the caliper but not back, so the brake drags and the car pulls; see why calipers stick. This mimics a stuck caliper but is actually the hose.
Soft or spongy pedal
A hose that balloons under pressure absorbs pedal effort, giving a soft, spongy feel that bleeding does not fix; see lines vs hoses. If the pedal is soft and the hoses are old and swollen, suspect them.
Leaks and cracks
Rubber hoses crack, chafe, and leak with age - look for cracks in the outer layer, wetness, or bulging under braking; see fluid leak signs and hose crimp leaks. A leaking hose is an immediate safety issue.
What to do
Replace bad hoses - they are inexpensive and critical; see brake hose replacement. Consider stainless-braided hoses for a firmer pedal. Bleed the system after. Fit quality pads and hardware.