Brake Fluid Flush

Complete brake fluid flush procedure to replace contaminated or degraded brake fluid with fresh DOT 3 fluid, ensuring safe brake system operation.

Warnings

Tools required

Fluids

• DOT 3 brake fluid — 1 qt

Preparation

1. Park vehicle on level ground and set parking brake firmly
2. Ensure transmission is in Park (automatic) or gear (manual)
3. Open hood and locate brake master cylinder reservoir on driver side firewall
4. Check brake fluid level and condition - dark or contaminated fluid confirms need for flush
5. Loosen all four wheel lug nuts 1/2 turn while vehicle is on ground
6. Raise vehicle using floor jack and support securely on jack stands at all four corners
7. Remove all four wheels for access to brake calipers
8. Clean dirt and debris from around all bleeder valves on each caliper to prevent contamination

Procedure

1. 1

   Empty master cylinder reservoir
   Using a turkey baster or brake fluid siphon, remove as much old brake fluid as possible from the master cylinder reservoir. Dispose of old fluid in a sealed container - do not pour down drains. Wipe reservoir interior clean with lint-free cloth if heavily contaminated.
2. 2

   Refill reservoir with fresh fluid
   Fill the master cylinder reservoir to the MAX line with fresh brake fluid of the type marked on the reservoir cap (DOT 3 or DOT 4 as specified for this vehicle) from a sealed container. Keep the brake fluid bottle and additional containers nearby as you will need to maintain this level throughout the entire procedure.
3. 3

   Prepare bleeding setup
   Attach clear vinyl tubing to the bleeder valve on the right rear caliper (passenger side rear). Place the other end of the tubing into a clear catch bottle. The tubing must remain submerged in a small amount of clean brake fluid in the catch bottle to prevent air from being drawn back into the system.
4. 4

   Bleed right rear caliper
   Have an assistant slowly depress the brake pedal fully and hold it down. Open the bleeder valve 1/2 to 3/4 turn with a 10mm wrench. Old fluid and air will flow through the tubing. When flow stops and pedal reaches the floor, close the bleeder valve BEFORE the assistant releases the pedal. Repeat this process until fluid flowing from bleeder is clean and light-colored, matching fresh fluid. Check and refill master cylinder reservoir every 3-4 pumps to prevent it from running dry.
   ⚠️CRITICAL: Never allow reservoir to run empty or air will enter the system. Check fluid level constantly during bleeding.
5. 5

   Bleed left rear caliper
   Move the bleeding setup to the left rear caliper (driver side rear). Repeat the bleeding process: assistant depresses pedal, open bleeder valve, close valve before releasing pedal. Continue until fresh, clean fluid flows from bleeder. Maintain master cylinder reservoir level throughout.
6. 6

   Bleed right front caliper
   Move the bleeding setup to the right front caliper (passenger side front). Repeat the bleeding process. The front calipers on the 2007 Ram 3500 have a single bleeder valve each. Continue until fresh fluid flows from the bleeder. Monitor reservoir level constantly. Continue until fresh fluid flows from all bleeders. Monitor reservoir level constantly.
7. 7

   Bleed left front caliper
   Move the bleeding setup to the left front caliper (driver side front). This is the final wheel position. Repeat the bleeding process at the single bleeder valve on this caliper. Continue until fresh, clean fluid flows. This completes the standard bleeding sequence: RR, LR, RF, LF.
8. 8

   Final master cylinder flush
   To ensure complete fluid replacement in the master cylinder, siphon out the reservoir one final time and refill with fresh DOT 3 fluid. Repeat the bleeding process at the left front caliper (closest to master cylinder) until fresh fluid appears, confirming complete system flush.
9. 9

   Check all bleeder valves
   Verify all bleeder valves at all four calipers are closed tight. Wipe away any spilled brake fluid from calipers, wheels, and brake components. Inspect for any leaks around bleeder valves.
10. 10

    Set final fluid level
    Fill master cylinder reservoir to the MAX line with fresh DOT 3 brake fluid. Securely install the reservoir cap. Wipe any spilled fluid from the master cylinder and surrounding painted surfaces immediately.

Reassembly

1. Reinstall all four wheels and hand-tighten lug nuts in a star pattern
2. Lower vehicle to the ground and remove jack stands
3. Torque lug nuts to manufacturer specification (typically 135 ft-lbs) in a star pattern
4. Pump brake pedal several times until pedal feels firm and consistent
5. Check master cylinder reservoir level one final time and top off if needed

Verification

• With engine off, pump brake pedal 10-15 times. Pedal should feel firm and hold steady pressure without sinking
• Start engine (brake booster will activate). Pedal should drop slightly but remain firm when depressed
• Check for any brake fluid leaks at all four bleeder valves and around master cylinder
• Verify master cylinder reservoir is at MAX line with cap secure
• Perform a low-speed brake test in a safe area: brakes should engage smoothly with no sponginess or pedal fade
• Perform a moderate brake test from 25-30 mph in a safe area: vehicle should stop straight with firm pedal feel
• If pedal feels soft or spongy, air remains in system and bleeding must be repeated
• Road test vehicle in safe conditions before returning to normal operation

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