Brake Fluid Flush

Replace brake fluid in all four brake calipers and lines to maintain optimal braking performance and prevent moisture contamination in the hydraulic system.

Warnings

Tools required

Parts

• ACDelco DOT 4 Brake Fluid × 2 — ACDelco 10-5060 or equivalent DOT 4

Fluids

• ACDelco DOT 4 Brake Fluid — 1.5 qt

Preparation

1. Park vehicle on level surface and place wheel chocks behind rear wheels
2. Ensure vehicle is in Park and power is OFF (not in accessory mode)
3. Allow brake system to cool completely if vehicle was recently driven (minimum 30 minutes)
4. Clean the master cylinder reservoir cap area to prevent contamination when opening
5. Verify you have at least 1.5 quarts of fresh, unopened ACDelco DOT 4 brake fluid with a recent manufacture date
6. Loosen all wheel lug nuts while vehicle is on ground (do not remove)
7. Raise vehicle and support securely on jack stands at all four corners
8. Remove all four wheels
9. Inspect brake lines, calipers, and master cylinder for leaks or damage before proceeding

Procedure

1. 1

   Prepare master cylinder reservoir
   Remove the master cylinder reservoir cap. Use a turkey baster or fluid transfer pump to remove as much old brake fluid as possible from the reservoir without completely emptying it. Wipe the inside of the reservoir with a clean, lint-free shop towel to remove sediment. Refill the reservoir to the MAX line with fresh ACDelco DOT 4 brake fluid. Keep the cap nearby but do not reinstall yet.
   ⚠Dispose of old brake fluid according to local hazardous waste regulations. Never pour brake fluid down drains or on the ground.
2. 2

   Bleed right rear caliper
   Starting with the right rear (passenger side rear) caliper, locate the bleeder screw on the back of the caliper body. Clean the bleeder screw area thoroughly. Attach clear plastic bleeder hose to the bleeder screw and place the other end in the catch container with enough fluid to submerge the hose end. Using the bleeder wrench, carefully loosen the bleeder screw 1/2 to 3/4 turn. Have an assistant slowly press the brake pedal to the floor and hold. Close the bleeder screw before the assistant releases the pedal. Repeat this process until clean, clear fluid with no air bubbles flows from the bleeder. Check and refill the master cylinder reservoir frequently to maintain fluid above the MIN line.
   ⚠️Monitor the master cylinder reservoir constantly during bleeding. If it empties, air will enter the system and you must start the entire bleeding sequence over.
   Torque spec

   Bleeder Screw10 Nm (7 lb-ft)
3. 3

   Bleed left rear caliper
   Move to the left rear (driver side rear) caliper. Repeat the bleeding procedure from Step 2: clean bleeder area, attach hose, open bleeder screw 1/2 to 3/4 turn, have assistant pump and hold brake pedal, close bleeder before releasing pedal. Continue until clean fluid with no air bubbles appears. Torque bleeder screw to specification when complete. Refill master cylinder reservoir to MAX line.
   Torque spec

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

   Bleed right front caliper
   Move to the right front (passenger side front) caliper. Repeat the bleeding procedure: clean bleeder area, attach hose to bleeder screw, open bleeder 1/2 to 3/4 turn, have assistant slowly depress and hold brake pedal, close bleeder before pedal is released. Continue until clean, bubble-free fluid flows. Torque bleeder screw to specification. Refill master cylinder reservoir to MAX line.
   ℹ️The front calipers may require more pumping cycles due to longer brake lines from the master cylinder.
   Torque spec

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

   Bleed left front caliper
   Move to the left front (driver side front) caliper, the final wheel in the bleeding sequence. Repeat the bleeding procedure one last time: clean bleeder area, attach hose, open bleeder screw 1/2 to 3/4 turn, have assistant depress and hold brake pedal slowly, close bleeder before releasing. Continue until clean fluid with no air bubbles is visible. Torque bleeder screw to specification. Refill master cylinder reservoir to MAX line.
   Torque spec

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

   Perform final bleeding verification
   Return to each caliper in the same sequence (RR, LR, RF, LF) and open each bleeder screw briefly while an assistant holds moderate pressure on the brake pedal to verify no air bubbles emerge. Close each bleeder and torque to specification. This confirms complete air removal from the system.
   Torque spec

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

   Finalize master cylinder
   Fill the master cylinder reservoir to the MAX line with fresh DOT 4 brake fluid. Wipe any spilled fluid from the reservoir area and surrounding components immediately with water. Install the reservoir cap and hand-tighten to specification. Ensure the cap is properly seated and secure.
   Torque spec

   Master Cylinder Cap4 Nm (3 lb-ft)
8. 8

   Reinstall wheels
   Reinstall all four wheels onto the vehicle. Start all lug nuts by hand to prevent cross-threading. Torque lug nuts to specification in a star pattern while vehicle is still on jack stands. Lower vehicle to the ground and perform final torque verification of all lug nuts in star pattern.
   Torque spec

   Wheel Lug Nuts140 Nm (103 lb-ft)
9. 9

   Test brake pedal feel
   With vehicle still in Park or on level ground with chocks, press the brake pedal firmly several times. The pedal should feel firm and consistent, rising to normal height. If pedal feels spongy or sinks slowly, air remains in the system and bleeding must be repeated. Pump the pedal 20-30 times to ensure proper feel before driving.
   ⚠️Do NOT drive the vehicle if the brake pedal feels soft, spongy, or sinks to the floor. This indicates air in the system or a hydraulic failure. Repeat bleeding procedure or seek professional service.

Reassembly

1. Verify all bleeder screws are closed and torqued to 10 Nm (7 lb-ft)
2. Verify all wheel lug nuts are torqued to 140 Nm (103 lb-ft) in star pattern
3. Verify master cylinder reservoir is filled to MAX line and cap is secure
4. Clean any brake fluid residue from wheels, calipers, and painted surfaces immediately with water
5. Dispose of used brake fluid at an appropriate hazardous waste facility

Verification

• Start vehicle and verify brake warning light is OFF on instrument cluster
• With vehicle stationary, press brake pedal firmly - it should feel solid and not sink
• Perform a low-speed test drive in a safe area (5-10 mph) and verify brakes engage smoothly and vehicle stops straight without pulling
• Perform several moderate brake applications from 25-30 mph in a safe area to verify proper braking force and pedal feel
• After test drive, inspect all four calipers for any signs of brake fluid leakage around bleeder screws
• Recheck master cylinder fluid level - it should remain at or near MAX line after test drive
• Verify regenerative braking integration feels normal and consistent with pre-service operation
• If any abnormality is detected (soft pedal, pulling, warning lights, leaks), do NOT drive vehicle and seek professional diagnosis immediately

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