Replacement of a single hydraulic brake line on a 2024 Model Y Long Range AWD. Involves draining/bleeding DOT 3 brake fluid and proper torquing of the line fittings.

Warnings

Tools required

Parts

• Replacement brake line (manufacturer-specified, pre-formed for this position) × 1 — Tesla OEM brake line for Model Y — verify by VIN
• Brake line fitting washers/seals (if equipped) × 1 — Per OEM specification

Fluids

• DOT 3 Brake Fluid — 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 low-voltage battery (located under the rear seat area on 2024 Model Y — refer to vehicle-specific access panel). Disable the vehicle in the touchscreen service menu before disconnecting if possible.
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. Loosen wheel lug nuts on the affected corner(s) before lifting.
7. Raise the vehicle at the manufacturer-specified jack points using pucks to protect the HV battery pack. Support on jack stands.
8. Remove the wheel(s) needed to access the brake line route.
9. Inspect the routing of the existing brake line and photograph clip/bracket positions before removal.
10. Top off the brake fluid reservoir with fresh DOT 3 to its MAX line so the system has reserve during the swap.

Procedure

1. 1

   Identify and access the failed brake line
   Trace the brake line from the master cylinder/iBooster outlet (or ABS modulator) to the affected caliper. Note all retaining clips, P-clamps, and bracket pass-throughs along the chassis. Clean both end fittings with brake cleaner so the flare nuts are clearly visible and free of debris.
   ⚠Do not bend or kink any adjacent brake or HV cabling while working underneath.
2. 2

   Cap the reservoir / minimize fluid loss
   To minimize drain-down, place a piece of plastic over the brake fluid reservoir and reseal the cap (or use a brake pedal depressor to lightly preload the master cylinder). This reduces the volume of fluid that siphons out when the line is opened.
3. 3

   Loosen the line fittings
   Using a proper flare-nut (line) wrench — never an open-end wrench — carefully break loose the fitting at the caliper/hose end first, then at the upstream end (hard line union, ABS block, or T-fitting). Apply penetrating oil and allow soak time if corroded. Stop and reassess if a fitting begins to round; damaged hard line unions on the ABS block require additional repair.
   ⚠Rounding a fitting on the ABS modulator can require modulator replacement — work slowly.
4. 4

   Release line retainers and remove
   Disengage all P-clips, push-in retainers, and any rubber grommets securing the line to the chassis or subframe. Fully unthread both fittings, place a catch pan beneath each end, and withdraw the line. Allow residual fluid to drain into the pan.
5. 5

   Compare and prep new line
   Lay the new line alongside the old one and confirm length, bend pattern, and fitting types match exactly. Pre-form any minor bends with a tubing bender — never by hand on hard line. Verify flare condition on both ends is clean and undamaged.
   ℹ️An incorrect-length or mis-routed line can rub through under suspension travel and fail catastrophically.
6. 6

   Install new brake line
   Route the new line following the original path. Start both end fittings BY HAND several turns to avoid cross-threading. Seat the line into all factory clips and brackets before final tightening so the line is not preloaded in tension or torsion.
   ⚠Cross-threaded fittings will weep under pressure. If a fitting won't start by hand, stop and inspect the threads.
7. 7

   Torque the line fittings
   Using a flare-nut crowfoot on a calibrated torque wrench, tighten both end fittings to the verified specification. Do not exceed spec — over-torquing will deform the flare and cause leakage.
   Torque spec

   Line Fittings20 Nm (15 lb-ft)
8. 8

   Bleed the affected corner
   Refill the reservoir with fresh DOT 3 brake fluid to MAX. Bleed the corner served by the new line using either pressure or vacuum bleeding at the caliper bleeder screw until clear, bubble-free fluid flows. Monitor the reservoir continuously and never let it drop below MIN. Torque the bleeder screw to the verified specification when complete.
   ⚠If the reservoir runs dry and air enters the iBooster/ABS module, a full Tesla Toolbox-assisted bleed may be required.
   Torque spec

   Bleeder Screw10 Nm (7 lb-ft)
9. 9

   Pressure check
   With the 12V reconnected and the vehicle 'on' (so the iBooster pressurizes the system), have an assistant firmly hold the brake pedal while you visually inspect every fitting and the new line for weeping or seepage. Repeat several pedal applications. Address any leak immediately by re-torquing or replacing the seal/flare.

Reassembly

1. Confirm all P-clips and retainers are fully seated and the line cannot contact moving suspension or steering components through full travel.
2. Top off the brake fluid reservoir to MAX with fresh DOT 3.
3. Reinstall the wheel(s). Snug lug nuts in a star pattern, then lower the vehicle.
4. Final-torque the wheel lug nuts in a star pattern to specification.
5. Reconnect the 12V low-voltage battery and reinstall any covers/trim.
6. Wake the vehicle and clear any chassis/ABS faults from the touchscreen service menu if present.

Verification

• With the vehicle awake, pump the brake pedal — pedal should be firm and high, not spongy or sinking.
• Check for any active warnings on the instrument cluster (ABS, ESC, brake fluid level, regen limited).
• Re-inspect the new line and both fittings for leaks after the first pedal applications.
• Perform a low-speed road test (start at walking pace) to confirm braking authority and straight-line stop behavior before higher-speed driving.
• Re-check torque on the wheel lug nuts after approximately 50 miles, per Tesla's recommendation.
• Note: Tesla recommends a complete brake fluid flush every 2 years regardless of mileage — if not recently performed, schedule a full flush.
• Recheck the line fittings for seepage 24-48 hours after the repair.

More procedures for this vehicle