Brake pedal travels to floor

JAMES OVERSTREET

MEMBER
2008 FORD EXPEDITION
5.7L
V8
2WD
AUTOMATIC
125,000 MILES

My brake pedal was starting to feel spongy. I replaced the master cylinder bench bled it then installed it. I then placed all four rotors and pads and had a full flush done on the brake fluid. A week later the brake pedal starts traveling to the floor. I checked all the calipers no leaks the fluid level is still full. I used a snapper computer and re-calibrated the abs system and still pedal travels to floor. The master cylinder was warrantied so I exchanged it and installed the new one re bled the system still pedal travels to the floor but the vehicle still stops.

3 Replies

BMDOUBLE

MECHANIC
1,139 POSTS

Remove the brake lines at the master cylinder and install screw in caps to block the flow, with the vehicle stopped and in park, retest with the vehicle running to see how they feel. If they feel solid now, then the issue is somewhere in either the front or rear brake line circuits. Block off one circuit at a time at the master cylinder to help isolate which one is giving you trouble and go from there. If the pedal still sinks with the master cylinder blocked off, the master cylinder is no good or you may need to use a power bleeder and you may want to try another brand of master cylinder. Now when you say that you used a scanner, I'm assuming you did the abs bleed procedure?