Complete replacement of all hydraulic brake lines on a 2024 Model S Long Range AWD, including hard lines and flexible hoses at all four corners, followed by a full system bleed. This is an intensive job requiring fabrication or pre-bent OEM lines and a full brake fluid flush.

Warnings

Tools required

Parts

• Front brake hoses (flexible) × 2 — Manufacturer-specified Model S front brake hose, left and right
• Rear brake hoses (flexible) × 2 — Manufacturer-specified Model S rear brake hose, left and right
• Hard brake lines (front and rear runs) × 1 — OEM pre-formed steel/coated hard lines or equivalent SAE J1401-compliant tubing
• Copper sealing washers for banjo fittings (if equipped) × 8 — Size per OEM banjo fitting
• Brake hose retaining clips × 8 — OEM line retaining clips

Fluids

• DOT 3 Brake Fluid (verify by VIN — newer builds may specify DOT 4) — 2 qt

Preparation

1. Park on level ground, place in P, engage parking brake.
2. Exit ALL doors with the 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 located in the front trunk (frunk) under the nose cowl panel. For 2021+ Plaid variants with a 16V lithium auxiliary battery under the rear seat, disconnect that unit instead — verify your specific build.
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. Place the vehicle in Transport / Jack Mode via the touchscreen BEFORE disconnecting 12V to prevent air suspension from dropping (if equipped).
7. Verify brake fluid specification (DOT 3 vs DOT 4) by VIN with a Tesla parts lookup before opening any new fluid.
8. Raise vehicle on a lift using Tesla-approved jack pad locations; remove all four wheels.
9. Photograph existing brake line routing, clip locations, and bracket positions for reassembly reference.
10. Have a scan tool capable of commanding the ABS/iBooster bleed routine staged and ready before opening the hydraulic system.

Procedure

1. 1

   Drain master cylinder reservoir
   Open the brake fluid reservoir cap (located on the iBooster assembly in the engine bay area behind the frunk liner). Use a clean fluid extractor to remove as much old fluid as possible. This minimizes spillage and reduces contamination of new fluid during the line swap.
   ⚠Do not allow the reservoir to run completely dry — air introduced into the iBooster may require extended scan-tool bleeding to recover.
2. 2

   Remove wheels and access calipers
   With the vehicle securely lifted, remove all four wheels. Set them aside. Inspect each caliper, flexible hose, and hard line junction. Note the routing of each line through chassis clips and brackets before disconnection.
   Torque spec

   Wheel Lug Nuts140 Nm (103 lb-ft)
3. 3

   Disconnect flexible hoses at calipers
   At each caliper, loosen the banjo bolt or flare fitting using a flare nut wrench to avoid rounding. Catch dripping fluid in a pan. Cap the caliper inlet immediately to prevent contamination. Discard old copper crush washers if banjo-style fittings are used.
4. 4

   Disconnect flexible hoses at hard line junctions
   Trace each flex hose to its chassis-mounted junction bracket. Hold the hard line nut with a backup wrench while loosening the flex hose nut to prevent twisting and damaging the hard line. Remove the retaining horseshoe clip before fully separating fittings.
5. 5

   Remove hard lines from chassis
   Working systematically from each corner toward the master cylinder/ABS modulator, release all chassis retaining clips and brackets holding the hard lines. Carefully extract the lines, noting any aluminum body contact points where chafe protection was installed. Be aware the HV battery pack is directly below — do not pry against the pack case.
   ⚠️The HV pack underbody is directly below the brake line routing. Do not drop tools onto, pry against, or scrape the pack enclosure.
   Torque spec

   Bracket Bolts102 Nm (75 lb-ft)

   Mounting Bolts27 Nm (20 lb-ft)
6. 6

   Disconnect lines at ABS/iBooster modulator
   At the modulator block, identify and label each port BEFORE loosening (front-left, front-right, rear-left, rear-right). Use a flare nut wrench on each fitting. Cap each port immediately. Do not allow brake fluid to drip onto adjacent electronics or aluminum bodywork.
7. 7

   Install new hard lines
   Route the new hard lines following the photographed/documented original path. Hand-thread each fitting at the modulator FIRST to avoid cross-threading, then install all chassis retaining clips and brackets. Ensure no line contacts a moving suspension component, exhaust-equivalent (drive unit cooling lines), or the HV pack enclosure.
   Torque spec

   Bracket Bolts102 Nm (75 lb-ft)

   Mounting Bolts27 Nm (20 lb-ft)
8. 8

   Tighten hard line fittings
   Once all lines are routed and clipped, snug then final-tighten each flare fitting at the modulator and at the corner junctions. Torque to OEM specification — refer to Tesla Service Manual. Over-torquing will deform the flare and cause leaks.
9. 9

   Install new flexible hoses
   Install each new flex hose with new copper sealing washers (if banjo-style). Ensure the hose is not twisted — most OEM hoses have alignment tabs or formed bends that index correctly only one way. Install retaining horseshoe clips at the chassis-side junction. Torque banjo or fitting hardware to OEM specification — refer to Tesla Service Manual.
10. 10

    Refill master cylinder reservoir
    Fill the reservoir with fresh, sealed DOT 3 brake fluid (or DOT 4 if VIN-specified). Keep the reservoir topped off throughout the bleed procedure — never let it run dry.
11. 11

    Perform manual gravity/pressure bleed at all four corners
    Starting at the corner farthest from the master cylinder (typically right rear, but verify with service manual sequence), open each bleeder screw and bleed using a pressure or vacuum bleeder until clear, bubble-free fluid emerges. Repeat for left rear, right front, left front. Maintain reservoir level throughout.
    Torque spec

    Bleeder Screw10 Nm (7 lb-ft)
12. 12

    Perform scan-tool ABS modulator bleed
    Reconnect the 12V battery temporarily and use a capable diagnostic tool to command the ABS/iBooster bleed routine. This cycles the modulator solenoids to purge trapped air. Re-bleed each corner manually after the actuation routine completes. Repeat the modulator routine and corner bleed until pedal is firm and fluid is clear at all four bleeders.
    ⚠Skipping the modulator bleed routine will result in a soft pedal and potential ABS faults. This step is mandatory on modern Model S.
    Torque spec

    Bleeder Screw10 Nm (7 lb-ft)
13. 13

    Final leak inspection
    With the system fully bled, have an assistant apply firm, sustained pedal pressure (or use a pressure bleeder held at ~30 psi) while you inspect every fitting — modulator ports, hard line junctions, flex hose ends, banjo bolts, and bleeder screws — for any sign of weeping. Correct any leak before proceeding.

Reassembly

1. Top off the brake fluid reservoir to the MAX line with fresh fluid and reinstall the cap.
2. Reinstall all four wheels and torque lug nuts in a star pattern.
3. Lower the vehicle to the ground.
4. Reconnect the 12V (or 16V) low-voltage battery if not already reconnected for the ABS bleed.
5. Close the frunk and verify all interior systems power up normally.
6. Exit Jack/Transport mode via the touchscreen; allow air suspension (if equipped) to re-level.

Verification

• Pedal feel: brake pedal should be firm within the first inch of travel with no sponginess. A soft pedal indicates trapped air — repeat the modulator bleed.
• Scan for DTCs: clear any ABS/iBooster codes set during the procedure and verify no codes return after a key cycle.
• Low-speed test in a safe area: verify ABS does not activate spuriously and that the vehicle stops straight without pulling.
• Re-inspect every fitting after the test drive for weeping fluid — heat and pressure cycles can reveal marginal seals.
• Verify regenerative braking and friction brake blending behave normally on the touchscreen energy display during the test drive.
• Document the service date — Tesla recommends brake fluid replacement every 2 years; this job resets that interval.
• Check brake fluid reservoir level after the test drive and top off to MAX if needed.

More procedures for this vehicle