I have a 91 4-door Explorer with 4 wheel drive and rear anti-lock brakes (RABS). While bleeding air from the brakes to try to solve a spongy pedal, the brake line that goes from the proportioning valve to the RABS pump “popped” and brake fluid began to drain onto the concrete.
Why does this brake line fail prematurely? Ford wrapped a spring around it for some reason, probably to dampen vibration, but the spring is an incompatible metal which corrodes the brake line in accelerated fashion. The result is total loss of rear brakes, a soft pedal, and a brake fluid leak.
Here is what to do about that problem. We will replace the broken brake line with Poly-Armour lines which are corrosion resistant, easy to bend, and which simply screw together with no flaring tool necessary.