Brake Fluid Flush

Complete brake fluid flush procedure to replace old brake fluid with fresh DOT 4 fluid, removing moisture and contaminants from the entire brake system.

Warnings

Tools required

Fluids

• ACDelco DOT 4 Brake Fluid — 1.5 qt

Preparation

1. Park vehicle on level surface and apply parking brake firmly
2. Place wheel chocks behind rear wheels
3. Verify you have at least 1.5 quarts of fresh, sealed ACDelco DOT 4 brake fluid
4. Loosen all four wheel lug nuts while vehicle is on ground (do not remove)
5. Raise vehicle using floor jack at manufacturer-specified jacking points
6. Support vehicle securely on jack stands at all four corners
7. Remove all four wheels completely
8. Locate brake caliper bleeder screws on all four wheels (rear of caliper body)
9. Clean area around each bleeder screw with brake cleaner and lint-free rag to prevent contamination
10. Locate master cylinder reservoir under hood (driver side, against firewall)
11. Remove master cylinder reservoir cap and inspect fluid level and condition

Procedure

1. 1

   Remove old fluid from master cylinder reservoir
   Using turkey baster or fluid transfer pump, remove as much old brake fluid as possible from the master cylinder reservoir. Do not allow any debris to enter the reservoir. Dispose of old fluid in appropriate container. Wipe inside of reservoir with clean, lint-free rag if contamination is visible. Refill reservoir to MAX line with fresh ACDelco DOT 4 brake fluid from sealed container.
   ⚠Keep reservoir covered when not actively working to prevent moisture absorption and contamination
2. 2

   Prepare bleeding setup at right rear wheel
   Begin with right rear wheel (furthest from master cylinder). Attach clear plastic tubing to bleeder screw, ensuring tight fit. Place other end of tubing into catch container with enough fresh brake fluid to submerge the tube end (prevents air from being drawn back). Verify master cylinder reservoir is at MAX line before proceeding.
3. 3

   Bleed right rear brake caliper
   Have assistant sit in driver seat. Using 10mm box-end wrench, loosen bleeder screw 1/2 to 3/4 turn (do not remove completely). Instruct assistant to slowly depress brake pedal to floor and hold. While pedal is held down, observe old dark fluid flowing through clear tubing. When flow stops, tighten bleeder screw to specification before releasing pedal. Repeat process 5-8 times until fluid runs completely clear with no bubbles. Check and refill master cylinder reservoir to MAX line after every 3-4 pedal strokes.
   ⚠️Never allow assistant to release brake pedal while bleeder screw is open, as this draws air into the system
   ⚠Monitor reservoir level constantly. Running dry introduces air into ABS system
   Torque spec

   Bleeder Screw10 Nm (7 lb-ft)
4. 4

   Bleed left rear brake caliper
   Move to left rear wheel (second furthest from master cylinder). Repeat identical bleeding procedure as right rear: attach tubing, verify reservoir level, loosen bleeder screw, have assistant depress and hold pedal, tighten bleeder screw before pedal release. Continue until fluid is completely clear with no air bubbles. Refill master cylinder reservoir to MAX line as needed.
   Torque spec

   Bleeder Screw10 Nm (7 lb-ft)
5. 5

   Bleed right front brake caliper
   Move to right front wheel (third in sequence). Repeat bleeding procedure: attach tubing to bleeder screw, check reservoir level, loosen bleeder screw 1/2 to 3/4 turn, have assistant slowly depress brake pedal to floor and hold, tighten bleeder screw to specification before pedal release. Repeat until fluid runs clear without bubbles. Maintain reservoir level at MAX line throughout process.
   Torque spec

   Bleeder Screw10 Nm (7 lb-ft)
6. 6

   Bleed left front brake caliper
   Move to left front wheel (closest to master cylinder, final position). Perform final bleeding procedure following same process: attach clear tubing, verify fluid level, open bleeder screw, pedal down and hold, close bleeder screw, release pedal. Continue until absolutely clear fluid with zero air bubbles is observed. This completes the bleeding sequence.
   Torque spec

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

   Perform secondary bleeding pass if needed
   If brake pedal feels soft or spongy, perform a second complete bleeding sequence in same order: right rear, left rear, right front, left front. Repeat bleeding process at each wheel until pedal firmness improves. Check all bleeder screws are tightened to specification after final bleeding.
   Torque spec

   Bleeder Screw10 Nm (7 lb-ft)
8. 8

   Final master cylinder service
   Fill master cylinder reservoir to MAX line with fresh ACDelco DOT 4 brake fluid. Wipe any spilled fluid from reservoir exterior and surrounding areas with water-dampened rag. Install reservoir cap and tighten hand-tight to specification. Inspect entire cap and reservoir area for leaks.
   Torque spec

   Master Cylinder Cap5 Nm (4 lb-ft)
9. 9

   Inspect all bleeder screws and brake components
   Visually inspect all four bleeder screws for proper tightness and absence of leaks. Check each caliper, brake line, and connection point for signs of fluid seepage. Verify no tools or rags were left near brake components. Wipe down any brake fluid residue from calipers, rotors, and suspension components.
   ⚠Brake fluid on rotors will cause noise and reduced braking. Clean thoroughly if contaminated
10. 10

    Reinstall wheels and lower vehicle
    Reinstall all four wheels, starting lug nuts by hand. Lower vehicle until wheels contact ground but vehicle weight is not fully on wheels. Torque all lug nuts to specification in star pattern. Fully lower vehicle and remove jack stands. Remove wheel chocks.
    Torque spec

    Wheel Lug Nuts140 Nm (103 lb-ft)

Reassembly

1. Ensure master cylinder reservoir is filled to MAX line with fresh DOT 4 fluid
2. Verify reservoir cap is installed and hand-tightened properly
3. Confirm all four bleeder screws are tightened to 10.0 Nm (7 lb-ft)
4. Double-check all lug nuts are torqued to 140 Nm (103 lb-ft) in star pattern
5. Dispose of old brake fluid at appropriate recycling facility or auto parts store

Verification

• Start engine and verify brake warning light is not illuminated on instrument cluster
• With engine running, pump brake pedal several times - pedal should feel firm and not sink to floor
• Perform stationary brake test: with engine running, apply firm brake pressure and hold for 30 seconds - pedal should not slowly sink
• Check master cylinder reservoir fluid level - should be at MAX line with no visible bubbles
• Inspect under vehicle at all four brake calipers for any signs of fluid leakage at bleeder screws
• Perform low-speed test drive in safe area (5-10 mph) to verify normal brake operation and pedal feel
• Perform moderate brake application from 25-30 mph in safe area - brakes should engage smoothly and evenly without pulling
• Verify ABS warning light is not illuminated after test drive
• Re-check master cylinder fluid level after test drive - should remain at MAX line
• If pedal feels soft, spongy, or requires pumping for firmness, repeat bleeding procedure or seek professional service immediately

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