4.5 brakes

Hydraulic Brake Bleed — SRAM (DOT Fluid)

Hydraulic Brake Bleed — SRAM (DOT Fluid). Step-by-step procedure for bike maintenance — tools, time, and what to watch out for.

Difficulty ★★★ advanced
Time ~30 min per brake
Applies to Bikes with SRAM hydraulic disc brakes

Tools

  • SRAM bleed kit (two syringes with Bleeding Edge fittings for newer Code/Level/G2)
  • SRAM DOT 5.1 fluid (do not substitute DOT 3 or DOT 4)
  • Torx T10 (lever bleed port screw on most SRAM)
  • 4mm hex (caliper Bleeding Edge)
  • nitrile gloves (DOT is corrosive to skin and paint)

Procedure

  1. Wear gloves and lay out absorbent rags around the bike

    DOT 5.1 attacks paint immediately.

  2. Remove wheel and pads

    Insert the SRAM bleed block.

  3. Position the lever horizontal

    (rotate clamp if needed).

  4. Prep the caliper syringe

    • Fill with about 1/3 DOT 5.1 fluid.
    • Hold tip up and tap to bring air bubbles to the top.
    • Push gently to expel air — fluid only at the tip.

  5. Prep the lever syringe

    • Fill 1/4 with fluid.
    • Same process to expel air from the syringe tip.

  6. Attach the caliper syringe

    to the caliper's Bleeding Edge port. Open the port using the 4mm hex (a quarter turn).

  7. Attach the lever syringe

    to the lever bleed port (remove T10 screw, thread on syringe).

  8. Push fluid from caliper syringe up through the system

    slowly — fluid (with air bubbles) flows up into the lever syringe.

  9. Continue pushing

    until the lever syringe is about 3/4 full.

  10. Close the caliper Bleeding Edge port

  11. Now push from the lever syringe down

    while the other end is closed — this pressurizes the system. Pull and push the lever syringe plunger several times to draw out any trapped air. You'll see bubbles coming up into the syringe.

  12. With pressure on the lever syringe

    , briefly squeeze the brake lever a few times to expel any bubbles trapped at the lever piston.

  13. Open the caliper port

    with the syringe slightly pulled (negative pressure) — draws any remaining air down to the caliper syringe.

  14. Close the caliper port

  15. Final lever bleed

    with the lever syringe attached and slight pressure, squeeze the lever fully and hold while a helper (or you, awkwardly) closes the lever port. This sets the firm lever feel.

  16. Remove the lever syringe

    and quickly install the bleed screw with T10.

  17. Remove the caliper syringe

    and reinstall the caliper bleed plug.

  18. Wipe everything thoroughly

    with isopropyl alcohol — DOT residue corrodes finishes.

  19. Reinstall pads and wheel

  20. Bed in the brakes

DOT fluid absorbs water from air. Use only fresh fluid from a sealed bottle; discard partially-used bottles after a year.