This procedure covers the replacement of a single damaged or corroded brake line section on a 2014 Ram 2500 4WD with 6.7L Cummins diesel engine, including flaring, fitting, and bleeding the brake system.

Warnings

Tools required

Parts

• Brake line tubing (steel or stainless, match OEM diameter) × 1 — Use OEM specification for diameter and material
• Brake line fittings (if not pre-flared) × 2 — Match thread size to existing fittings
• Brake line retaining clips × 2 — Use OEM or equivalent

Fluids

• Mopar DOT 4 Brake Fluid — 0.5 qt

Preparation

1. Park vehicle on level surface and apply parking brake firmly. Place wheel chocks behind wheels that will remain on ground.
2. Open hood and locate brake master cylinder reservoir. Check fluid level and condition. If fluid is dark or contaminated, consider full system flush.
3. Identify which brake line requires replacement by tracing from the damaged section to connection points. Note routing, clips, and mounting points.
4. Measure the damaged brake line section carefully, accounting for bends and length. Add 6 inches to measurements for safety margin.
5. Raise vehicle using floor jack at appropriate frame lift points and support with jack stands. Never work under a vehicle supported only by a jack.
6. Remove wheel(s) if brake line runs near wheel well or suspension components to improve access.
7. Clean all brake line fittings and connections with wire brush and penetrating oil. Allow 10-15 minutes for penetrating oil to work on corroded fittings.

Procedure

1. 1

   Prepare brake fluid reservoir
   Using a turkey baster or fluid transfer pump, remove brake fluid from the master cylinder reservoir down to the minimum line. This minimizes fluid loss and spillage during line removal. Dispose of old brake fluid properly. Place absorbent material and catch pans under the work area.
2. 2

   Disconnect damaged brake line at fittings
   Using the appropriate size flare nut wrench, carefully loosen the brake line fittings at both ends of the damaged section. Hold the junction block or component fitting with a backup wrench to prevent twisting. If fittings are severely corroded and will not turn, apply more penetrating oil and use a six-point flare nut wrench to avoid rounding. Once loose, unscrew by hand and immediately cap or plug open ports to prevent contamination.
   ⚠Never use standard open-end wrenches on brake line fittings. They will round the soft brass or steel fittings, making removal extremely difficult.
3. 3

   Remove brake line retaining clips
   Locate all retaining clips, brackets, and mounting points holding the damaged brake line to the frame, body, or suspension. Remove clips carefully using a flat-blade screwdriver or pliers. Note the exact position and orientation of each clip for reinstallation. On this vehicle, brake lines typically follow the frame rail with clips every 12-18 inches.
4. 4

   Cut and remove damaged section
   If replacing only a portion of the line rather than the full run, use a tube cutter to make clean, square cuts on either side of the damaged area. Ensure sufficient straight line remains on each end (minimum 1 inch) for proper flaring. Remove the damaged section completely and inspect surrounding lines for additional corrosion or damage.
5. 5

   Fabricate replacement brake line
   Cut new brake line tubing to the measured length plus allowance for bends. Using the tube bender, carefully form bends to match the original routing, avoiding kinks. Bends should have a minimum radius of 3 times the tube diameter. Test-fit the new line along the routing path before flaring to ensure proper fit and clearance from hot exhaust components, suspension travel, and sharp edges.
   ⚠Kinked brake lines will restrict fluid flow and cause brake failure. If a kink occurs during bending, discard that section and start with new tubing.
6. 6

   Create double flares on line ends
   Using the double flaring tool, create proper SAE double flares (also called inverted flares) on both ends of the new brake line. Ensure tubing is cut square and deburred inside and outside. Insert tubing into the flaring tool bar at the correct depth per tool instructions (typically flush with the bar surface). Form the initial bubble, then complete the double flare. Inspect flares for cracks, uneven edges, or incomplete formation. Remake any questionable flares.
   ⚠️Improperly formed flares will leak under pressure and cause brake failure. Each flare must be smooth, concentric, and fully formed. If uncertain about flare quality, have it inspected by a professional or use pre-flared brake line.
7. 7

   Route and install new brake line
   Route the new brake line along the original path, ensuring it follows the same protection points and maintains clearance from moving parts, exhaust components, and sharp edges. Install all retaining clips and brackets in their original positions. Clips should hold the line securely without crushing or deforming it. Verify minimum 1-inch clearance from exhaust and at least 0.5-inch clearance from any moving suspension or steering components through full travel range.
8. 8

   Connect brake line fittings
   Thread both brake line fittings into their respective ports by hand first to ensure proper thread engagement. Fittings should thread smoothly without resistance. If resistance is felt, stop and check for cross-threading. Once hand-tight, use the flare nut wrench to tighten fittings to proper torque. Hold the junction block or component with a backup wrench while tightening. Tighten until snug plus approximately 1/6 turn (60 degrees). Do not overtighten as this will damage the flare and cause leaks.
   ⚠Brake line fittings do not have a specified torque value and are tightened by feel. Overtightening will collapse the flare and cause leaks. Undertightening will allow leaks under pressure.
9. 9

   Refill brake fluid reservoir
   Fill the master cylinder reservoir with fresh Mopar DOT 4 brake fluid to the MAX line. Use only new fluid from an unopened container. Keep reservoir filled above the MIN line throughout the bleeding process to prevent air from entering the system.
10. 10

    Bleed affected brake circuit
    Beginning with the wheel furthest from the master cylinder (typically right rear), attach clear tubing to the bleeder screw and submerge the other end in a container with clean brake fluid. Have an assistant pump the brake pedal 3-5 times and hold pressure. Open the bleeder screw using the proper wrench to allow fluid and air to escape. Close the bleeder screw before the pedal reaches the floor. Repeat until no air bubbles are visible in the tubing. Move to the next furthest wheel and repeat. Standard bleeding sequence for this vehicle: right rear, left rear, right front, left front. Check and refill reservoir frequently.
    ⚠️Never allow the brake pedal to return to the top position while a bleeder screw is open. This will draw air into the system through the bleeder threads.
    ⚠ABS-equipped vehicles may require additional bleeding procedures using a scan tool to cycle the ABS valves. If pedal feel remains soft after standard bleeding, professional ABS bleeding may be required.
    Torque spec

    Bleeder Screw10 Nm (7 lb-ft)
11. 11

    Inspect all connections for leaks
    With the system bled, have an assistant firmly apply brake pedal pressure and hold. Carefully inspect all new brake line connections and fittings for any signs of fluid seepage or leakage. Wipe all fittings dry first, then observe for 30 seconds under full pedal pressure. If any leaks are detected, release pressure, slightly tighten the fitting, and retest. If leaks persist, the flare may be damaged and the line end must be re-cut and re-flared.
    ⚠️Any brake fluid leak, no matter how small, is unacceptable and will lead to brake failure. Do not proceed until all leaks are eliminated.
12. 12

    Test brake pedal operation
    With the engine off, pump the brake pedal several times. The pedal should become firm and maintain height. If the pedal sinks slowly to the floor, air remains in the system or a leak exists. If the pedal feels spongy, repeat bleeding procedure. The pedal should feel solid with no more than 2 inches of travel before resistance is felt. Start the engine and verify power brake assist is functioning. Pedal should drop slightly when engine starts.

Reassembly

1. Reinstall wheels if removed and torque lug nuts to specification in a star pattern.
2. Lower vehicle from jack stands carefully and remove chocks.
3. Top off brake fluid reservoir to MAX line with fresh Mopar DOT 4 fluid.
4. Clean any spilled brake fluid from components, frame, and body panels immediately to prevent paint damage.
5. Verify all tools and materials are removed from under vehicle and engine bay.

Verification

• Before driving, perform a stationary brake test: with the engine running, apply firm brake pedal pressure for 60 seconds. Pedal should remain firm and not sink. If pedal sinks, there is a leak or air in the system.
• Perform a low-speed brake test in a safe area: drive at 5-10 mph and apply brakes firmly. Vehicle should stop straight with no pulling to either side. Repeat several times.
• Perform a higher-speed brake test in a safe area: drive at 25-30 mph and apply brakes progressively harder. Brakes should engage smoothly and firmly with no pedal pulsation or vehicle pulling.
• After first test drive, re-inspect all new brake line connections for any signs of leakage with the system at operating temperature.
• Monitor brake pedal feel for the first 100 miles. Any change in pedal height or firmness requires immediate inspection.
• Check brake fluid reservoir level after test drives. Any significant fluid loss indicates a leak that must be found and corrected immediately.

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