Complete replacement of all hydraulic brake lines on a 2024 Model Y Performance AWD, including hard lines and flexible hoses at all four corners, followed by full system bleed. This is a safety-critical hydraulic job — any air or leak compromises stopping power.

Warnings

Tools required

Parts

• Front flexible brake hose (LH) × 1 — OEM Tesla Model Y front brake hose
• Front flexible brake hose (RH) × 1 — OEM Tesla Model Y front brake hose
• Rear flexible brake hose (LH) × 1 — OEM Tesla Model Y rear brake hose
• Rear flexible brake hose (RH) × 1 — OEM Tesla Model Y rear brake hose
• Hard line set (front-to-rear and crossover lines) × 1 — OEM Tesla Model Y hydraulic hard line kit — refer to Service Manual for the specific lines required
• Copper/aluminum sealing washers for banjo fittings (if equipped) × 8 — OEM specification
• Brake line retaining clips × 12 — OEM specification

Fluids

• DOT 3 Brake Fluid (sealed, fresh container) — 2 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 Y, the 12V (Li-ion) battery is accessible — refer to the Service Manual for the exact access panel for this 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 vehicle in Transport/Jack Mode via the touchscreen BEFORE disconnecting 12V if the suspension or service mode requires it; on Model Y this disables certain regen/parking brake behaviors.
7. Loosen all four lug nuts while wheels are on the ground.
8. Lift vehicle at all four Tesla-specified jack pad locations using puck adapters; support on EV-rated jack stands.
9. Remove all four wheels and set aside on rubber mats.
10. Place a catch pan beneath the vehicle and lay down absorbent material along brake line routing.
11. Cover painted surfaces, wheel wells, and any plastic trim near line routing with shop rags or plastic sheeting.
12. Photograph existing brake line routing, clip locations, and bracket positions for reassembly reference.

Procedure

1. 1

   Open and cap the brake fluid reservoir
   Locate the brake fluid reservoir in the front trunk area. Clean around the cap before opening to prevent contamination. Use a fluid extractor to remove as much old fluid as possible from the reservoir to minimize spillage during line replacement. Do not let the reservoir run completely dry while lines are still pressurized in the system.
   ⚠Do not allow brake fluid to drip onto the front trunk liner or painted surfaces — it will cause permanent damage.
2. 2

   Document and release routing
   Trace each existing brake line from the master cylinder/booster outlet through the chassis to each caliper. Photograph every clip, retainer, and bracket. Note the orientation of flare fittings. This is critical because aftermarket replacement lines may not be pre-bent identically.
3. 3

   Disconnect flexible hoses at calipers
   At each corner, place a catch pan beneath the caliper. Using a flare nut wrench, loosen the banjo bolt or flare fitting where the flexible hose meets the caliper. Allow fluid to drain. If the caliper uses a banjo bolt, discard the sealing washers — they are single-use.
   ⚠Use a flare nut wrench, not an open-end wrench, on flare fittings. Open-end wrenches will round the soft fitting.
4. 4

   Disconnect flexible hoses at chassis brackets
   At the chassis-side end of each flexible hose, hold the hose hex with one wrench while loosening the hard-line flare nut with a flare wrench. Remove the retaining clip securing the hose to the chassis bracket. Do not twist the flexible hose during removal.
5. 5

   Remove hard lines from chassis
   Working systematically from the master cylinder outward, disconnect each hard line at its unions and at the ABS modulator. Release each line from its routing clips along the floor pan and subframe. Carefully lower lines without bending or kinking; preserve them as templates for the new lines if needed. Cap or plug all open ports on the ABS modulator immediately to prevent contamination.
   ⚠️The ABS modulator is sensitive to dirt and air. Cap every open port the moment a line is disconnected.
   ⚠Verify that no orange HV cable runs alongside the brake line you are removing. If routing is shared, STOP and consult a Tesla-certified technician.
6. 6

   Compare new lines against old
   Lay new hard lines and flexible hoses next to the originals. Verify length, bend pattern, and fitting types match. Pre-bend any sections that need slight adjustment using a proper line bender — never bend by hand, as kinks will restrict flow.
7. 7

   Install new hard lines
   Starting at the ABS modulator, thread each new hard line fitting in by hand FIRST to avoid cross-threading. Once started by hand, snug with a flare nut wrench. Route the line through original clip locations; install new retaining clips where needed. Torque hard line flare fittings to OEM specification — refer to Tesla Service Manual.
   ⚠Cross-threading a flare fitting will ruin both the line and the modulator port. Always start by hand.
8. 8

   Install new flexible hoses
   Install each flexible hose at the chassis bracket end first. Insert through the bracket, install the retaining clip, then thread the hard-line flare fitting into the hose end. Route the hose so it does not contact suspension components through full steering and travel range. At the caliper end, use NEW sealing washers if the caliper uses a banjo fitting. Torque all flare fittings to OEM specification — refer to Tesla Service Manual.
   ⚠Cycle the steering lock-to-lock and compress/extend the suspension to confirm no hose contacts tire, suspension, or HV cabling.
9. 9

   Reinstall any disturbed bracketry
   If any line brackets, caliper bracket bolts, or caliper bolts were disturbed during line routing, reinstall and torque them to spec. Apply threadlocker where specified by Tesla.
   Torque spec

   Bracket Bolts102 Nm (75 lb-ft)

   Caliper Bolts88 Nm (65 lb-ft)

   Caliper Slide Pin Bolts35 Nm (26 lb-ft)

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

    Refill reservoir with fresh DOT 3
    Fill the master cylinder reservoir to the MAX line with sealed, fresh DOT 3 brake fluid only. Do NOT use DOT 5 or any silicone fluid. Keep the reservoir topped off throughout the entire bleed procedure — if it runs dry, air will enter the ABS modulator and require a service-tool bleed.
    ⚠️Never mix brake fluid types. Only DOT 3 (or DOT 4 if approved by Tesla Service Manual for this VIN) is acceptable.
11. 11

    Bleed the system — manual sequence
    With an assistant or pressure bleeder, bleed in the manufacturer-specified sequence (typically furthest caliper first: RR, LR, RF, LF — but VERIFY SEQUENCE WITH TESLA SERVICE MANUAL for this build). At each caliper, attach a clear hose to the bleeder screw into a catch bottle, open the bleeder, flush until clean fluid runs with no air bubbles, then close. Torque each bleeder screw carefully — they are easy to snap.
    ⚠Bleeder screws are brass and break easily. Do not exceed the specified torque.
    Torque spec

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

    ABS modulator bleed (if pedal not firm)
    If pedal feel is soft after manual bleed, the ABS modulator likely retains air. Tesla service software can command an ABS pump cycle to purge it. This typically requires a Tesla service center or a compatible diagnostic tool. Do NOT attempt to drive the vehicle with a soft pedal.
    ⚠️A soft brake pedal indicates air in the system. Driving the vehicle in this state risks brake failure.
13. 13

    Final leak check
    With reservoir topped off, have an assistant apply firm pedal pressure (around 40-50 lb) and hold for 30 seconds. Inspect every fitting, hose, and the ABS modulator with a flashlight for any wetness or weeping. Repeat at each caliper and chassis junction. Wipe each fitting dry and re-inspect after a second pedal application to catch slow seeps.

Reassembly

1. Reinstall all four wheels; hand-thread lug nuts to avoid cross-threading.
2. Lower vehicle until tires just touch the ground, then torque lug nuts in a star pattern.
3. Lower vehicle fully and re-torque lug nuts in star pattern as final check.
4. Top off brake fluid reservoir to MAX line; install reservoir cap securely.
5. Reconnect 12V low-voltage battery (negative terminal last).
6. Wipe down any spilled fluid; brake fluid residue will damage paint over time.
7. Allow vehicle to wake and complete its self-check before moving.

Verification

• With vehicle off but awake, press the brake pedal firmly several times — pedal should feel firm and consistent, not spongy or sinking.
• Start the vehicle (Ready mode). Check the touchscreen for any ABS, brake, or traction control warnings. If any appear, do not drive.
• At very low speed (under 5 mph) in a safe area, perform a gentle stop. Pedal should feel firm with no pulling to either side.
• Gradually increase test speed to 25 mph and perform a moderate stop. Verify straight-line braking and firm pedal.
• Perform one harder stop from 35-40 mph in a safe area to confirm ABS engagement does not produce a soft pedal afterward.
• Recheck all fittings for leaks after the test drive — heat and pressure cycling can reveal weeps that static testing misses.
• Recheck reservoir fluid level after 24 hours and after the first 100 miles.
• Note: Tesla recommends brake fluid replacement every 2 years regardless of mileage. Log this service date — your next brake fluid change is due in 2 years.

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