Replace a single hydraulic brake line on a 2024 Tesla Model 3 Long Range AWD, including proper bleeding of the affected corner. This is a hydraulic-only job — no HV systems are involved, but the standard Tesla LV disconnect procedure still applies.

Warnings

Tools required

Parts

• Replacement brake line (manufacturer-specified for affected corner) × 1 — OEM Tesla Model 3 brake line — match by location (LF/RF/LR/RR)
• Copper or OEM-spec sealing washers (if used at fitting) × 2 — OEM-spec, single-use

Fluids

• DOT 4 Brake Fluid (Tesla-specified) — 1 qt

Preparation

1. Park on level ground, place in P, and engage the parking brake via the touchscreen.
2. Exit ALL doors with the key fob/phone key carried 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 3, the 12V is typically a lithium unit — access per the architecture notes (behind right rear seat back panel on most years; some 2024+ have lithium 12V under floor). Follow the current Tesla Service Manual for the correct access location on this VIN.
4. DO NOT touch, cut, or pierce ANY orange cable — these are high-voltage and lethal. If you encounter an orange cable, an HV component, or are unsure if a system is de-energized: STOP and consult a Tesla-certified technician.
5. Identify which brake line is being replaced (front-left, front-right, rear-left, or rear-right, or a chassis hard line). Confirm the routing end-to-end before disassembly.
6. Place fender covers over painted surfaces near the brake fluid reservoir.
7. Loosen the wheel lug nuts on the affected corner(s) while the vehicle is on the ground.
8. Raise the vehicle using the manufacturer-specified jack points and Tesla-approved pucks. Support on jack stands rated for EV curb weight. Remove the wheel(s).

Procedure

1. 1

   Cap the reservoir and prepare for fluid loss
   Open the brake fluid reservoir cap briefly, top up to MAX with fresh DOT 4 if low, then loosely reinstall the cap. Some technicians prefer to seal the reservoir with plastic wrap under the cap to slow gravity drain when the line is opened. Place a catch pan under the work area.
2. 2

   Clean fittings before opening
   Spray brake parts cleaner on both end fittings of the line being replaced and wipe clean. Removing road grime from the flare nuts before turning them dramatically reduces the chance of seizing or rounding.
3. 3

   Loosen the line fittings
   Using a flare-nut/line wrench, crack loose the fitting at each end of the line. If the line connects to a flexible hose at one end, use a backup wrench on the hex of the hose end to prevent it from twisting. Do NOT fully remove yet — just confirm both fittings will break free.
   ⚠If a fitting will not break free with reasonable torque, stop and apply penetrating oil. Forcing it will twist the steel line or strip the fitting.
4. 4

   Release line retainers and brackets
   Locate and release every retaining clip, P-clamp, and grommet securing the line to the chassis or subframe along its run. Photograph the routing before removal so the new line follows the identical path. If any bracket bolts must be removed for access, note their location for reinstallation.
   Torque spec

   Bracket Bolts102 Nm (75 lb-ft)
5. 5

   Remove the old brake line
   Fully unthread both end fittings and let the line drain into the catch pan. Cap or plug the open ports at the caliper/hose/master side immediately to prevent contamination and minimize fluid loss. Remove the old line from the vehicle without bending adjacent lines.
   ⚠Do not let brake fluid drip onto suspension bushings, wiring, or painted surfaces.
6. 6

   Compare old and new line
   Lay the new line next to the old one. Confirm length, bend pattern, fitting sizes (inverted flare vs. bubble flare), and any inline retainers match exactly. A mismatched line will not seal properly and will fail under pressure.
7. 7

   Install the new line — start fittings by hand
   Route the new line along the documented path. Thread BOTH end fittings in by hand several turns before tightening either one. This prevents cross-threading, which is the single most common cause of repeat leaks on hydraulic line jobs.
   ⚠️A cross-threaded brake fitting may seem to seal during a static check but will fail under pedal pressure. If it does not start smoothly by hand, back it out and retry.
8. 8

   Torque the line fittings
   Using a flare-nut crow's-foot or line-wrench torque adapter, tighten both end fittings to spec. If using a crow's-foot at 90° to the wrench, account for the change in effective length per the torque wrench manufacturer's instructions.
   Torque spec

   Line Fittings20 Nm (15 lb-ft)
9. 9

   Reinstall retainers and brackets
   Seat the line into every original clip and grommet. Reinstall any bracket bolts removed for access. Confirm the line does not contact suspension, steering, or rotating components throughout the full range of suspension and (for front lines) steering travel.
   Torque spec

   Bracket Bolts102 Nm (75 lb-ft)

   Mounting Bolts27 Nm (20 lb-ft)
10. 10

    Reconnect the 12V battery
    Reconnect the 12V low-voltage battery before bleeding so the iBooster/electronic brake system can be cycled if needed and so the touchscreen/parking brake function correctly. Allow the vehicle to fully wake and complete its self-checks before proceeding.
    ℹ️Tesla brake systems use an electronic booster. Bleeding procedures may require service-mode actuation. If air remains trapped after manual bleeding, the system may need a Tesla service tool to actuate the booster — refer to the Tesla Service Manual.
11. 11

    Bleed the affected corner (and full system if fluid is overdue)
    Top off the reservoir with fresh DOT 4 fluid. Bleed the corner served by the replaced line until clear, bubble-free fluid emerges. Use the bleeder screw on the caliper with a clear hose into a catch bottle. If the front master/booster area was opened or air may have migrated, bleed all four corners in the manufacturer-specified sequence — refer to the Tesla Service Manual for the correct sequence on this VIN. Keep the reservoir above MIN at all times during bleeding.
    ⚠Do not let the reservoir run dry — this introduces air into the master cylinder/booster and may require a service-tool-assisted bleed to recover.
    Torque spec

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

    Pressure test for leaks
    With the system bled, have a helper firmly press and hold the brake pedal while you inspect both new fittings and the full length of the line for any seepage. Any wet fitting must be addressed — do not 'snug a little more' beyond spec. Diagnose, reseat, or replace as needed.

Reassembly

1. Verify reservoir is filled to MAX with fresh DOT 4 fluid and reinstall the cap fully.
2. Reinstall the wheel and torque lug nuts in a star pattern.
3. Lower the vehicle to the ground and re-torque lug nuts in a star pattern with the wheel loaded.
4. Wipe down any residual brake fluid from suspension components and the caliper with brake parts cleaner.
5. Confirm 12V battery hold-down/terminal hardware is properly secured — refer to the Tesla Service Manual for terminal torque on the lithium 12V (do not guess).

Verification

• Pedal feel: with the vehicle awake and brake-by-wire active, the pedal should feel firm and consistent — not spongy. Spongy pedal = air still in the system.
• Check the touchscreen for any ABS, traction control, or brake warning indicators. Clear any related alerts and confirm none reappear.
• Perform a low-speed roll test (under 5 mph) in a safe area and apply the brakes firmly. Confirm straight, even stopping with no pull and no warnings.
• Re-inspect both new fittings after the test drive — heat cycling and pressure cycling can reveal a marginal seal that didn't show on the static check.
• Recheck reservoir level and top off to MAX with DOT 4 if needed.
• Reminder: Tesla's published recommendation is to replace brake fluid every 2 years regardless of mileage. Log this service date — if the fluid was original and only the affected corner was bled, schedule a full flush at the 2-year mark.

More procedures for this vehicle