Replace a single brake line on a 2024 Tesla Model S Long Range AWD. This is a hydraulic-only job (no HV systems involved), but requires careful handling due to the vehicle's regenerative-braking-assisted hydraulic system and DOT-spec fluid requirements.

Warnings

Tools required

Parts

• Replacement brake line (manufacturer-specified for the affected circuit) × 1 — OEM Tesla brake line for 2024 Model S — verify by VIN
• Crush washers / sealing washers (if line uses banjo fittings) × 2 — OEM specification

Fluids

• DOT 3 Brake Fluid (verify spec on master cylinder cap by VIN — newer Model S may require DOT 4) — 1 qt

Preparation

1. Park on level ground, place in P, engage parking brake.
2. Exit ALL doors with key fob away from the vehicle. Wait at least 2 minutes for HV systems to fully de-energize, even on this non-HV job.
3. Disconnect the 12V low-voltage battery. On 2024 Model S Long Range, the 12V (lithium) battery is located in the front trunk under the nose cowl panel — remove the cowl trim, then disconnect negative first.
4. DO NOT touch, cut, or pierce ANY orange cable — these are high-voltage and lethal.
5. If at any point you encounter an orange cable, an HV component, or are unsure if a system is de-energized: STOP and consult a Tesla-certified technician.
6. Confirm brake fluid specification (DOT 3 vs DOT 4) by checking the master cylinder reservoir cap and/or VIN-based service info before opening the system.
7. Chock the wheels that will remain on the ground.
8. Identify which brake line is being replaced (front LH/RH, rear LH/RH, or a hard-line section) and confirm routing from master cylinder/ABS unit to the caliper.
9. Place absorbent material under the line's path to catch fluid drips.
10. Top off or note the fluid level in the master cylinder before opening the system.

Procedure

1. 1

   Lift vehicle and remove wheel
   Using Tesla-approved lift pad adapters at the factory jacking points, raise the corner of the vehicle serving the affected brake line and support on jack stands. Remove the wheel to access the caliper and brake line routing.
   ⚠Model S curb weight exceeds 4,700 lb — use jack stands rated accordingly. Never rely on the jack alone.
2. 2

   Cap or clamp the master cylinder reservoir
   To minimize fluid loss and air ingestion, seal the master cylinder reservoir (vacuum cap method) or use a fluid stopper. Do NOT pinch-clamp modern flexible brake hoses with locking pliers — use a proper rubber hose clamp tool only if absolutely necessary, and never on hard lines.
3. 3

   Loosen fittings before disconnection
   Using a flare-nut (line) wrench, break loose both end fittings of the affected brake line BEFORE fully removing any retaining clips. This prevents twisting the line if a fitting is seized. If a fitting is corroded or rounded, stop and reassess — do not strip the fitting.
   ⚠Never use an open-end wrench on hydraulic fittings — it will round the flats.
4. 4

   Release retaining clips and brackets
   Remove any P-clips, push-in retainers, or routing brackets securing the line along the chassis or suspension. Note routing carefully — photograph before removal for correct re-installation.
5. 5

   Disconnect line at both ends
   Fully unscrew the fittings at both ends of the line, allowing fluid to drain into the catch pan. Plug both open ports immediately with brake line caps to prevent contamination and excessive fluid loss from the master cylinder.
   ⚠Do not allow the master cylinder reservoir to run dry — top up periodically if fluid loss is significant.
6. 6

   Compare and route new line
   Lay the new line next to the old one to verify length, end-fitting types, and any pre-formed bends match exactly. Route the new line along the original path, ensuring no contact with moving suspension components, hot brake parts, or sharp edges.
   ℹ️If the replacement is a hard line and bends do not match, use a proper tubing bender — do not bend by hand, which will kink the line.
7. 7

   Install and start fittings by hand
   Thread both end fittings in by hand first to avoid cross-threading the soft fitting threads. Only after both ends are started should you tighten either side.
8. 8

   Tighten fittings and reinstall retainers
   Tighten both line fittings to OEM specification — refer to Tesla Service Manual for the specific brake line fitting torque (typical range, but do not guess). Reinstall all P-clips and routing brackets to original positions.
   ⚠Over-torquing flare fittings deforms the seat and causes leaks. Snug + a measured turn per service manual is the correct method.
9. 9

   Bleed the affected brake circuit
   Refill the master cylinder with the correct DOT-spec fluid. Bleed the affected corner using the bleeder screw on the caliper. Tesla's electronic brake booster may require a scan-tool-assisted bleed procedure to fully purge the modulator — perform a manual gravity/vacuum bleed first, then verify pedal feel. If pedal is soft or spongy, a Toolbox-assisted ABS/booster bleed is required.
   ⚠Do not pump the brake pedal hard with the system open — the iBooster-style assist can pull air deep into the modulator.
   Torque spec

   Bleeder Screw10 Nm (7 lb-ft)
10. 10

    Top off and seal reservoir
    Fill the master cylinder reservoir to the MAX line with fresh DOT-spec fluid. Reinstall the cap. Wipe down all fittings with brake cleaner so leaks are visible during testing.

Reassembly

1. Reinstall the wheel and hand-thread all lug nuts.
2. Lower the vehicle until the wheel just contacts the ground, then torque the lug nuts in a star pattern.
3. Reconnect the 12V battery (positive first, then negative) and reinstall the frunk nose cowl trim.
4. Allow the vehicle to wake and complete its system self-checks before driving.

Verification

• With the vehicle awake, press the brake pedal firmly multiple times — pedal should be firm with consistent travel, not spongy.
• Check the dash for any ABS, traction control, or brake system warning messages on the touchscreen.
• Visually inspect both fittings on the new line for weeping fluid after pedal pressure is applied.
• Inspect the line routing once more for any contact with suspension or driveline components at full steering lock and through suspension travel.
• Road test at low speed in a safe area: confirm straight-line braking, no pulling, and no warning messages. Then test at moderate speed.
• Re-inspect fittings for leaks after the road test.
• Recommend brake fluid replacement every 2 years per Tesla's published guidance — log this service date.
• If pedal remains soft after manual bleeding, the vehicle requires a Tesla Toolbox / scan-tool-commanded ABS/booster bleed at a qualified shop.

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