Brake lines, one of the most important components in a vehicle's braking system, carry hydraulic brake fluid from the master cylinder to each wheel. They may be steel, rubber, or a combination of both materials. Leaking brake lines result in degraded braking performance, and those that are aging or damaged could fail at any time. In either case, you should replace them immediately to keep your vehicle safe.
Steel Brake Lines
Though brake lines can be made from softer materials, rigid steel brake lines are more resistant to damage from road debris. They are especially useful in off-road conditions where the chances of a brake line puncture are higher. These tough and rigid tubes are the most common type that carries fluid from the master cylinder, though they connect to flexible brake lines closer to the wheel. These types have flared ends to ensure a leak-proof connection and are available in different lengths.
Stainless Steel Lines
Unlike the rigid brake lines that leave the master cylinder, stainless steel brake lines are flexible hoses. Also called braided brake lines, they consist of a Teflon inner tube surrounded by a stainless steel braid. Short in length, these flexible brake lines connect the hard steel line to the brake calliper or wheel cylinder. This is necessary because the wheel of any vehicle is free to move, and a rigid part would not allow it, thereby resulting in failure. Most factory-equipped cars use a short polymeric tube with a thick rubber coating. Stainless steel types are better protected from road debris and do not expand as much when pressurised. As a result, drivers experience more responsive brakes. Some stainless steel lines have a clear plastic covering over the braid. This prevents contaminants from working their way into the braid, resulting in longer service life. Because of the braid that covers the inner tube, inspection of a stainless steel line is difficult. A good rule of thumb is to replace this type of line every two or three years if used on standard road cars.
Considerations When Buying Brake Lines
When buying a replacement brake line, ensure that it is the same length as the original and has matching flares and fittings. Rigid steel lines have bends to provide extra slack and some flexibility. This reduces the stress on connection points, minimising the risk of failure. Bends also help route lines to provide clearance from other components. OEM brake lines are pre-bent to correctly fit a particular vehicle's components as are aftermarket lines made specifically for a vehicle. However, it is possible to buy straight steel lines, cut them to length, flare the ends, and bend them to the correct shape using the proper tools.