Replace a single hydraulic brake line on a 2024 Model 3 Performance. This is a hydraulic-only job — no HV systems are touched, but a full bleed of the affected corner is required afterward.

Warnings

Tools required

Parts

• Brake line (specific corner being replaced) × 1 — OEM Tesla Model 3 Performance brake line for the affected position — verify by VIN
• Copper/aluminum sealing washers (if used at fitting) × 2 — Per OEM specification for the fitting type

Fluids

• DOT 4 Brake Fluid (Tesla specification — note: database listing of DOT 3 is incorrect for this chassis; Model 3 uses DOT 4) — 1 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 (or Li-ion low-voltage) battery. On 2024 Model 3 Performance, the low-voltage battery is typically located behind the right rear seat back panel; some 2024 builds use a lithium 12V unit under the floor — verify location before disconnecting.
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. Identify the exact brake line being replaced (front/rear, left/right, hard line vs. flexible hose) and confirm replacement part matches by VIN.
7. Place the vehicle in 'Jack Mode' / 'Transport Mode' via the touchscreen (Service menu) before lifting to disable suspension self-leveling and prevent unintended motion.
8. Lift the vehicle using only Tesla-approved jack pad locations on the rocker pinch welds. Support on stands rated for EV weight.
9. Cover painted bodywork and the HV pack underside near the work area with absorbent shop towels to catch fluid drips.
10. Top off the brake fluid reservoir with fresh DOT 4 before starting — a full reservoir reduces air ingestion during line removal.

Procedure

1. 1

   Remove wheel at affected corner
   Loosen lug nuts, raise the corner, support on a stand, then remove the wheel to access the caliper, hub, and brake line routing.
2. 2

   Inspect and document line routing
   Before removing anything, photograph the brake line routing, all retaining clips, brackets, and fitting orientations. Model 3 lines route along the underbody and through chassis brackets that are easy to misroute on reinstall.
3. 3

   Clamp upstream and prepare to catch fluid
   If replacing a flexible hose, use a brake hose clamp upstream to minimize reservoir drain-down. Position a catch bottle under the lower fitting. Have a vacuum cap or plug ready for the open hard-line end.
   ⚠Do not clamp a hard steel/composite line — clamping can deform and weaken it. Hose clamps are for rubber/flexible sections only.
4. 4

   Loosen line fittings with a flare-nut wrench
   Using a proper flare-nut (line) wrench — never an open-end wrench — break loose the fittings at both ends of the line. If a fitting is seized, apply penetrating oil and work it gently; rounding the fitting will require replacing the mating component.
   ⚠Open-end wrenches will round brake fittings. Use a six-point flare-nut wrench only.
5. 5

   Release retaining clips and brackets
   Pop the line out of any chassis-mounted retainer clips and remove any bracket bolts securing the line along its run. Note clip positions for reinstallation.
   Torque spec

   Bracket Bolts102 Nm (75 lb-ft)
6. 6

   Remove the old brake line
   Fully unthread both fittings and remove the line. Immediately cap or plug the open ports on the caliper, hard line, or master-side fitting to prevent contamination and excessive fluid loss.
7. 7

   Compare new line to old
   Lay the new line next to the old one to confirm length, end fitting types, banjo vs. flare ends, and bracket tab positions match exactly. A mismatch indicates the wrong part — do not attempt to force-fit.
8. 8

   Install new brake line — start fittings by hand
   Thread both end fittings in by hand for several turns before applying any wrench. Cross-threading a brake fitting destroys the mating component. Route the line exactly as the original, seating it in all clips and brackets before final tightening.
   ⚠Never use thread sealant or PTFE tape on brake fittings — they are metal-to-metal flare seals.
9. 9

   Torque line fittings
   Using a flare-nut crowfoot on a torque wrench (or a calibrated feel if a crowfoot is unavailable, then verify by checking for leaks under pressure), torque both fittings to the specified value. Reinstall any retaining clips and bracket bolts.
   Torque spec

   Line Fittings20 Nm (15 lb-ft)

   Bracket Bolts102 Nm (75 lb-ft)
10. 10

    Bleed the affected circuit
    Reconnect the 12V battery temporarily is NOT required for a manual bleed. Top off the reservoir with fresh DOT 4. Bleed the corner where the line was replaced using the bleeder screw on the caliper — pump-and-hold or vacuum bleed until clean, bubble-free fluid flows. Keep the reservoir topped up throughout; never let it run dry. If the master-cylinder side of the system was opened, a full four-corner bleed in the manufacturer-specified sequence is required — refer to Tesla Service Manual for sequence.
    ⚠️If the reservoir runs dry during bleeding, air enters the ABS/iBooster module and a scan-tool-assisted bleed may be required to fully purge it.
    Torque spec

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

    Pressure check for leaks
    With the system bled, have an assistant firmly press and hold the brake pedal while you inspect every fitting and the full length of the new line for weeping or drips. Wipe each fitting dry and re-check after 60 seconds of held pressure.

Reassembly

1. Confirm all bracket bolts and retainer clips are seated and torqued.
2. Top off the brake fluid reservoir to the MAX line with fresh DOT 4.
3. Reinstall the wheel and torque lug nuts in a star pattern.
4. Reconnect the 12V low-voltage battery and reinstall its access panel.
5. Lower the vehicle to the ground and exit Jack/Transport Mode via the touchscreen.

Verification

• With the vehicle on the ground and powered on, press the brake pedal firmly several times — pedal must be firm and high, not soft or sinking.
• Check the touchscreen for any ABS, traction control, or brake warning indicators. Any active alert means the bleed is incomplete or a sensor was disturbed.
• Inspect the new line and both fittings one more time after the first pedal application — leaks often only appear under full system pressure.
• Perform a low-speed road test in a safe area: confirm the vehicle tracks straight under hard friction braking (disable regen-only stopping by applying firm pedal pressure). Regen can mask a soft pedal — you must verify with the friction brakes specifically.
• Re-check fluid level after the road test and top off if needed.
• Note the service date — Tesla recommends full brake fluid replacement every 2 years regardless of mileage. If the existing fluid was not flushed during this repair, schedule a full flush at the next interval.

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