If the pedal effort when braking is noticeably greater than usual, check the brake booster with the vehicle stationary.
You will need: a flat-blade screwdriver and a rubber bulb.

1. With the engine off, press the brake pedal five or six times. Keep the brake pedal depressed and start the engine. The brake pedal should move forward. If this does not happen, check...

2. ...the tightness of the vacuum hose fit in the intake pipe (for clarity, the throttle assembly has been removed)...

3. ...and a vacuum booster (the battery shelf has been removed for clarity).
4. To check the operation of the check valve, remove the battery shelf (see "Removing and installing the battery mounting shelf").

5. Use a screwdriver to pry up the vacuum hose fitting…

6. …and remove it from the brake booster sealing bushing hole.

7. Insert the bulb tip firmly into the end of the vacuum hose that connected the hose to the vacuum booster and squeeze it. Air should come out of the bulb through the valve.

8. Release the bulb. If it remains compressed, the valve is OK. If there is no bulb, you can blow through the valve with your mouth.
9. If the check valve leaks air in both directions, replace the vacuum hose assembly with the valve, to do this…

10. …holding the seal with a screwdriver…
NOTE: Throttle body removed for clarity.

11. …remove the vacuum hose fitting from the intake pipe opening…

12. …and remove the vacuum hose assembly with the check valve.
13. Install the parts in the reverse order of removal.
For more information, please visit the website (FORDBOOK)