DFC - Dynamic Friction Company Brake Lines

Solid metal brake lines are typically used along the underbody of a vehicle. They run from the master cylinder or ABS unit to about the edge of the inner fender. Flexible brake hoses are needed at the brake calipers, which have to move with the suspension. The flexible hoses are short, and run from the caliper to the solid brake line. Car manufacturers usually install more cost-effective rubber brake hoses from the factory. These rubber hoses can degrade over time. Eventually, they may swell, crack, or leak due to age.

Rubber brake hoses will perform well in normal driving and infrequent hard stops. However, in more demanding performance driving, high heat and pressure from the brake fluid will cause rubber hoses to swell. This will result in a soft brake pedal and reduced braking performance. Stainless steel braided brake hoses are a more durable, high-performance alternative to standard rubber brake hoses. Stainless braided brake hoses are constructed of a teflon inner tube wrapped in a stainless steel braided outer layer. This construction prevents swelling and provides a firm and consistent brake pedal feel under hard braking. While stainless braided brake hoses are more expensive, they don’t degrade like rubber brake hoses. They will last much longer and save you money in the long run.

Poor Braking Performance: The vehicle suddenly takes noticeably longer to stop. A brake line may be damaged or restricted. Other brake components can also cause poor braking performance. This may include the master cylinder, brake calipers, or worn brake pads and rotors.

Brake Warning Light Is On: The brake warning light can either indicate there is a loss of brake fluid, or the parking brake is engaged. Verify the parking brake is off and check the brake fluid level in the master cylinder reservoir. If the fluid is low, inspect for leaks.

Visible Brake Fluid Leak: Brake fluid leaking under the vehicle can indicate a corroded or damaged metal brake line, or a cracked or damaged rubber brake hose. It’s also possible that a brake caliper piston (disc brakes) or a wheel cylinder (drum brakes) could be leaking. Brake fluid may leak out rapidly while under pressure when applying the brakes.

Visible Brake Line Damage: Brake line damage may or may not result in brake fluid leaks. Corrosion on metal brake lines can weaken them over time, causing them to leak. Metal brake lines could also be bent or dented from road debris, resulting in a brake fluid restriction. Cracking or splitting of rubber brake hoses can occur with age, causing them to leak. Swelling may also be visible on rubber brake hoses, causing a loss of braking performance.

Solid metal brake lines are not repairable and must always be replaced when they fail. Metal brake lines require fabrication before they can be replaced. They are sold in bulk rolls and must be straightened, bent, and flared to fit before installing. Research your vehicle to purchase the correct diameter brake lines and correct size fittings. 

What You’ll Need To Replace Solid Brake Lines:

• - Roll of brake line in the correct diameter*
• - Brake line fittings in the correct sizes*
• - Pipe cutting tool
• - Pipe bending tool
• - Pipe flaring kit
• - Pipe deburring tool
• - Set of flare nut wrenches
• - Brake fluid

*Brake line comes in a variety of diameters. Brake line fittings come in a variety of sizes. Research your vehicle to identify and purchase the correct fit.

What You’ll Need To Replace Brake Hoses:

Brake hoses can be swapped out with a direct replacement of the same length. Always replace brake hoses in pairs (both front or both rear) or complete sets. You will need:

• Correct length replacement rubber or stainless braided brake hoses*
• Set of flare nut wrenches
• Brake fluid

*Brake hoses come in a variety of lengths. Research your vehicle to identify and purchase the correct fit.

Replacing The Brake Lines Or Hoses

1. Safely raise and support the vehicle.
2. Remove the wheel(s) at the location you are replacing the brake line or hose.
3. Loosen and drain the brake line or hose.
4. Disconnect the fittings at both ends and remove.
5. If replacing a brake hose, install the new hose and tighten the fittings. Proceed to Step 17.
6. If replacing a brake line, carefully remove it from the vehicle.
7. Precisely measure the metal brake line along all bends with a length of string.
8. Use a pipe cutter to cut the new metal brake line to the correct length.
9. Remove metal flash with a deburring tool.
10. Place the new fittings over the brake line before flaring.
11. Identify the correct flare type (SAE/double flare or DIN/ISO bubble flare)
12. Flare the line according to the flaring tool instructions.
13. Lay the new brake line next to the old one.
14. Use a tube bender to match each bend of the old line precisely. (CAUTION: Bending errors cannot be corrected.)
15. Carefully reinstall the metal brake line from one end. Hand tighten the fitting.
16. Fully tighten brake line fittings when the line is in the correct position.
17. Verify all brake line and hose fittings are tight.
18. Fill the master cylinder with brake fluid.
19. Bleed the brakes to purge all air from the brake system. A brake bleeder is recommended. 

Most modern vehicles have four brake lines. A brake line runs from the master cylinder to each wheel. Each wheel has a brake hose that connects the metal line to the brake caliper. Brake hoses are needed to allow movement with the vehicle suspension. Older vehicles may have a single brake line to the rear axle that has a T-split to each rear wheel.

Brake lines don’t have a maintenance schedule. Several factors can affect the longevity of brake lines. This can include age, environment, damage, and driving conditions. Corrosion on metal brake lines can weaken them over time, causing them to leak. Metal brake lines could also be bent or dented from road debris, resulting in a brake fluid restriction. Cracking or splitting of rubber brake hoses can occur with age, causing them to leak. Swelling may also be visible on rubber brake hoses, causing a loss of braking performance. Have your brake system inspected at least once a year as preventative maintenance.