Rust Pressure on Brake Lines

I wrote in the Early February about replacing both the brake calipers on my family’s 1992 Dodge B250 van after the old caliper pistons repeatedly seized up and failed to release pressure on the brake pads. A kind reader wrote to suggest that I should also check to make sure none of the van’s brake lines were being squeezed by rust.

Since my youth spent in Detroit attempting to hold a rusty 1977 Dodge together with Bondo, I tend to think of rust as something that weakens steel and turns it to dust. However, rust has another way to cause mischief. As the reader pointed out, rust bubbles can extend outward from the base metal and take up more space than the original metal did. Layers of rust built up on a brake hose bracket or other brake fitting can actually push hard enough on a brake hose to impede the flow of brake fluid. Hydraulic pressure may still activate the brake pads, but once the brake pedal is released, a brake hose squeezed by rust restricts the release of brake fluid pressure. The brake pads stay pressed against the brake rotor, causing heat, wear, drop in fuel economy, steering pulling to one side or other problems. I checked the brackets supporting the brake lines on my Dodge van and did not find significant rust build up. A good wire brushing and fresh paint can restore some brake hardware. Brake hydraulic hoses compressed by rust may have lost their shape and need to be replaced.

A master mechanic and shop owner recently told me another place to watch for rust exerting pressure is the lug nuts. Some original equipment lug nuts are steel clad with a layer of chromed metal. Rust builds up on the inner lug nut and slightly bulges out the chrome cladding. Maybe the next time a tire goes flat, the vehicle owner discovers the lug nut wrench no longer fits the lug nuts because they are swollen with rust.