1979 9" could have either 1/2" or 3/8" backing plate bolts.

1957/83 F100 & 1975/86 F150

1957/60 used the small bearing. 1961/67 used the large bearing. 1968/72 could have either the large bearing or the one used w/the 9 3/8" rear axle.

1973 used the large bearing. 1974/79 used either the large bearing, or the axle bearing/seal combination. 1974/79: There's no way to know until you pull an axle.

1980/86 used the large bearing.

Bearings have BIN's (Bearing Industry Numbers) stamped on them. Parts stores, bearing shops go by these numbers.

D8AZ-1225-C (replaced C9AZ-1225-A & C1SZ-1225-A) .. Large Axle Bearing ~ Marked: F208-HL // C9AZ-1225-A marked 88128 or FPP or F208AKK // C1SZ-1225-A marked 88128.

E0TZ-1S177-CA (replaced C9AZ-1177-A & B7A-1177-A) .. Axle Seal-Use with large axle bearing.
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D4AZ-1225-A .. Axle Beariing/Seal Combination (Ford did not sell the bearing only) / Marked: U-399-A-1.

D4AZ-1177-A .. Axle Seal.
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D0TZ-1225-A .. Axle Bearing-Use with 9 3/8" ring gear / Marked: 1580.

C9VY-1177-A .. Axle Seal-Use with 9 3/8" ring gear.

These same parts (including the 9 3/8" [1966/73 Lincoln, some LTD/Birds & Mercs]) were also used on specific Passenger Cars.