Component Test - Brake Master Cylinder - Bypass Condition

WARNING: This page is about a different car, the 2018 Ford F-550 Super Duty, 2018 Ford F-450 Super Duty, 2018 Ford F-350 Super Duty, and 2018 Ford F-250 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.

Inspect the master cylinder.
Disconnect the brake tubes from the master cylinder.
NOTE: Make sure the outlet port plugs do not show signs of leakage.

Plug the outlet ports of the master cylinder.
Lightly apply the brakes and hold for 10 seconds. Release the brakes and then reapply with heavy force. If brake pedal height cannot be maintained, the brake master cylinder has an internal leak and a new brake master cylinder must be installed. Refer to: Brake Master Cylinder . Refer to: Brake Master Cylinder - Vehicles With: Hydro-Boost™ .

If brake pedal height is maintained, reinstall brake tubes and tighten to specification. Refer to: Specifications . After installation, bleed the brake system. REFER to: Brake System Pressure Bleeding .