Hydraulic Brake Bleed — Shimano (Mineral Oil)

Procedure

1. Remove the wheel and brake pads

   from the caliper you're bleeding (so the pistons aren't pushed too far apart and to keep oil off the pads).

2. Insert the bleed block

   into the caliper (a plastic spacer that holds the pistons in their bored position).

3. Rotate the brake lever

   so it sits horizontal — the bleed port on top of the lever should be flat (loosen the lever clamp if needed and rotate, then snug back).

4. Remove the bleed port screw

   on top of the lever using a small hex (typically 2.5mm).

5. Thread the funnel

   into the bleed port. It includes a small stopper plug — leave the stopper in until you're ready to add oil.

6. Fill the funnel

   with fresh Shimano mineral oil to about half full.

7. Open the caliper bleed nipple

   with a 7mm wrench (only loosen 1/8 turn). Attach a clear vinyl tube to the nipple, with the other end in a catch container to capture old oil.

8. Pull the brake lever slowly to the bar and hold

   — old oil and air bubbles flow out through the caliper nipple.

9. Close the caliper nipple

   before releasing the lever (otherwise air sucks back in).

10. Release the lever

11. Top up the funnel

    as the oil level drops.

12. Repeat steps 8–11

    until the fluid running out at the caliper is clear and bubble-free, and lever feel is firm.

13. Tap the caliper and hose

    with the handle of a screwdriver while pulling the lever — knocks loose bubbles trapped in the hose.

14. For final bleed

    with no bubbles coming through, gently squeeze the lever many times rapidly to push any remaining tiny bubbles up to the funnel.

15. Insert the funnel stopper plug

16. Unscrew the funnel

    carefully — quickly cap the bleed port with the bleed screw and tighten.

17. Wipe everything down

    with a rag dampened with isopropyl alcohol.

18. Reinstall pads and wheel

19. Test lever feel

    — should be firm with a defined bite point. If spongy, repeat bleed.

20. Bed in the brakes

    even though the pads are old — the pad/rotor contact may have changed.