Brake Bleed - All Four

This procedure removes air from the brake hydraulic system on all four wheels to restore proper brake pedal feel and braking performance.

Warnings

Tools required

Parts

• ACDelco DOT 4 Brake Fluid × 1 — Use OEM specification

Fluids

• ACDelco DOT 4 Brake Fluid — 1 qt

Preparation

1. Park vehicle on level ground and ensure it is in Park with the parking brake engaged
2. Turn off the vehicle completely and remove key from proximity
3. Verify you have at least 1 quart of fresh, sealed ACDelco DOT 4 brake fluid
4. Loosen all wheel lug nuts while vehicle is on ground, but do not remove
5. Safely raise and support vehicle on all four corners using jack stands at designated lift points
6. Remove all four wheels and set aside
7. Clean brake bleeder screws on all four calipers with brake cleaner to prevent dirt from entering system
8. Locate brake fluid reservoir under hood and remove cap - check fluid level is at MAX line

Procedure

1. 1

   Prepare brake fluid reservoir
   Remove brake fluid reservoir cap. If fluid is dark or contaminated, use turkey baster to remove old fluid (dispose properly). Fill reservoir to MAX line with fresh DOT 4 brake fluid. Keep extra fluid nearby to top off during bleeding. Never let reservoir drop below MIN line during this procedure.
   ⚠️Monitor reservoir level after every wheel. Running the reservoir dry will introduce air and require starting over.
2. 2

   Begin bleeding sequence - Right Rear wheel
   Start with the wheel furthest from the master cylinder (right rear). Attach clear plastic hose to bleeder screw and submerge other end in catch container with small amount of clean brake fluid. Have assistant press brake pedal slowly 3-4 times and hold pressure. Open bleeder screw 1/4 to 1/2 turn. Fluid and air will flow into hose. When flow stops and pedal reaches floor, close bleeder screw BEFORE assistant releases pedal. Repeat until no air bubbles appear in hose (typically 5-10 cycles).
   ⚠Bleeder screw is brass and easily damaged. Use proper size wrench and torque to only 10 Nm (7 lb-ft). Do not overtighten.
   ⚠️Close bleeder screw BEFORE releasing brake pedal or air will be drawn back into system.
   Torque spec

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

   Check and refill reservoir after right rear
   After completing right rear wheel, check brake fluid reservoir and refill to MAX line with fresh DOT 4 fluid. Wipe up any spilled fluid immediately.
4. 4

   Bleed Left Rear wheel
   Move to left rear wheel (second furthest from master cylinder). Repeat same bleeding process: attach hose to bleeder screw, assistant pumps and holds pedal, open bleeder 1/4 to 1/2 turn, observe fluid flow, close bleeder before releasing pedal. Continue until no air bubbles appear. Torque bleeder screw to specification when complete.
   ⚠️Ensure bleeder screw is fully closed before assistant releases brake pedal.
   Torque spec

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

   Check and refill reservoir after left rear
   Check brake fluid reservoir level and top off to MAX line with fresh DOT 4 brake fluid. Monitor for any leaks around bleeder screws already serviced.
6. 6

   Bleed Right Front wheel
   Move to right front wheel (third in sequence). Repeat bleeding process: attach clear hose to bleeder screw, assistant pumps and holds brake pedal, open bleeder screw 1/4 to 1/2 turn while pedal is held, observe fluid flow until bubble-free, close bleeder before pedal release. Torque bleeder screw properly.
   ⚠Front bleeder screws may be in different positions than rear. Ensure proper access and wrench fit before applying force.
   Torque spec

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

   Check and refill reservoir after right front
   Check brake fluid reservoir and refill to MAX line. You should have used approximately 0.5-0.75 quarts by this point if bleeding properly.
8. 8

   Bleed Left Front wheel
   Complete bleeding sequence at left front wheel (closest to master cylinder, last in sequence). Attach hose to bleeder screw and repeat process: pump pedal 3-4 times and hold, open bleeder 1/4 to 1/2 turn, observe flow until no air bubbles, close bleeder before releasing pedal. Continue until fluid runs completely clear with zero bubbles. Torque bleeder screw to 10 Nm.
   ℹ️This is the final wheel. Ensure absolutely no air bubbles remain before closing bleeder.
   Torque spec

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

   Final reservoir fill and cap installation
   Fill brake fluid reservoir to MAX line one final time. Wipe reservoir and cap threads clean. Install reservoir cap securely. Inspect all four bleeder screws for proper torque and no leaks.
10. 10

    Reinstall wheels and lower vehicle
    Reinstall all four wheels. Thread lug nuts by hand first to prevent cross-threading. Snug lug nuts in star pattern with hand tools. Lower vehicle to ground. Torque all lug nuts to 190 Nm (140 lb-ft) in star pattern using torque wrench.
    ⚠️Improperly torqued lug nuts can cause wheel detachment. Always use torque wrench and star pattern.
    Torque spec

    Wheel Lug Nuts136 Nm (100 lb-ft)
11. 11

    Pedal test and system verification
    With vehicle still in Park and parking brake engaged, pump brake pedal 15-20 times. Pedal should feel firm and consistent. Press and hold pedal with significant force for 30 seconds - it should not slowly sink to floor. If pedal feels spongy or sinks, air remains in system and bleeding must be repeated.

Reassembly

1. Ensure all four bleeder screws are torqued to 10 Nm and not leaking
2. Verify brake fluid reservoir is at MAX line with cap properly installed
3. Confirm all wheels are installed with lug nuts torqued to 140 Nm in star pattern
4. Dispose of used brake fluid properly at recycling center - never pour down drain

Verification

• Start vehicle and verify no brake warning lights on instrument cluster
• Pump brake pedal - should achieve firm pedal within 2-3 pumps with consistent height
• Perform test drive in safe area at low speed (under 15 mph) - verify brakes engage smoothly without pulling to either side
• Perform 5-10 moderate braking events from 25-30 mph to normalize brake system with regenerative braking
• Check for firm pedal feel and straight-line braking with no pulsation or vibration
• After test drive, recheck brake fluid reservoir level and inspect all bleeder screws for leaks
• Monitor brake pedal feel over next few days - any sponginess indicates air in system requiring re-bleeding

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