Except Cougar

Normally, brake booster-to-master cylinder push rod should not require adjustment. If brake booster is suspected of having an improper push rod length, check and adjust push rod length as necessary. Go to next step.
Fabricate push rod gauge according to specified dimensions. See Fig 1, Fig 2 or Fig 3 . Remove master cylinder from power brake booster (without removing hydraulic lines), and set aside. Support master cylinder to prevent damage to hydraulic lines.
Start engine and place gauge over push rod. See Fig 4. Adjust push rod nut to provide light tension of about 5 lbs. (2.3 kg) against gauge. Reinstall master cylinder.

Fig 1: Identifying Master Cylinder Push Rod Gauge (Continental, Sable & Taurus)

Courtesy of FORD MOTOR CO.

Fig 2: Identifying Master Cylinder Push Rod Gauge (Crown Victoria, Grand Marquis & Town Car)

Courtesy of FORD MOTOR CO.

Fig 3: Identifying Master Cylinder Push Rod Gauge (Mustang)

Courtesy of FORD MOTOR CO.

Fig 4: Measuring Brake Booster Push Rod Length

Courtesy of FORD MOTOR CO.