The first-generation Ford Bronco, built for the 1966 through 1977 model years, was a compact body-on-frame four-wheel-drive on a 92-inch wheelbase, sold in three body codes: the U13 open roadster with no doors or top, the U14 half-cab pickup, and the U15 wagon. Ford launched it with a 170-cubic-inch inline-six and added the 289-cubic-inch V8 during 1966. The 302 V8 replaced the 289 for 1969, and the base six grew from 170 to 200 cubic inches for 1973. Suspension used coil springs at the front Dana 30 axle and leaf springs at the Ford 9-inch rear, a combination Ford kept for the whole generation. The Dana 30 front axle was replaced by the heavier-duty Dana 44 for 1971. Front drum brakes carried through 1975 before power front disc brakes arrived for 1976. The open U13 roadster was dropped after 1968, and the U14 half-cab pickup continued through 1972; the U15 wagon became the only body style for 1973 and carried the model to its 1977 finish.
At a glance
- Years: 1966-1977 (first generation, the "early Bronco")
- Body styles: U13 open roadster (1966-1968), U14 half-cab pickup (1966-1972), U15 wagon (1966-1977, the only body style from 1973)
- Engines: 170 then 200 cubic-inch inline-six; 289 then 302 cubic-inch V8
- Front axle: Dana 30 (1966-1970), Dana 44 (1971-1977)
- Rear axle: Ford 9-inch (all years)
- Suspension: front coil springs, rear leaf springs
- Brakes: front drums 1966-1975, power front discs 1976-1977
- Wheelbase: 92 inches throughout
Year-by-year changes
| Year | Engines | Drivetrain & brakes | Notable changes |
|---|---|---|---|
| 1966 | 170 I6 standard; 289 V8 added during the year | Dana 30 front, Ford 9-inch rear, front drums, 3-speed manual | Launch year of the compact Bronco on a 92-inch wheelbase; U13 roadster, U14 half-cab, U15 wagon all offered |
| 1967 | 170 I6; 289 V8 | Dana 30 front, Ford 9-inch rear, front drums | Sport appearance and trim package debuts; federal safety equipment such as a dual-circuit brake master cylinder added across Ford lines for 1967 |
| 1968 | 170 I6; 289 V8 | Dana 30 front, Ford 9-inch rear, front drums | Side marker lights added for federal rules; final year for the open U13 roadster body |
| 1969 | 170 I6; 302 V8 | Dana 30 front, Ford 9-inch rear, front drums | Roadster dropped; range narrows to the U14 half-cab and U15 wagon; 302 V8 replaces the 289 |
| 1970 | 170 I6; 302 V8 | Dana 30 front, Ford 9-inch rear, front drums | Last model year for the Dana 30 front axle |
| 1971 | 170 I6; 302 V8 | Dana 44 front, Ford 9-inch rear, front drums | Heavier-duty Dana 44 front axle replaces the Dana 30 |
| 1972 | 170 I6; 302 V8 | Dana 44 front, Ford 9-inch rear, front drums | Final model year for the U14 half-cab pickup; industry shift to SAE net power ratings, so published outputs drop versus the earlier gross figures |
| 1973 | 200 I6; 302 V8 | Dana 44 front, Ford 9-inch rear, front drums, C4 automatic now available | U15 wagon becomes the only body style after the half-cab is dropped; 200 six replaces the 170; C4 3-speed automatic and power steering become available; larger bumpers and detail changes during the early-1970s federal updates |
| 1974 | 200 I6; 302 V8 | Dana 44 front, Ford 9-inch rear, front drums | Continued wagon-only production with the Dana 44 front axle |
| 1975 | 200 I6; 302 V8 | Dana 44 front, Ford 9-inch rear, front drums | Last model year for front drum brakes; the V8 gains a catalytic converter and requires unleaded fuel |
| 1976 | 200 I6; 302 V8 | Dana 44 front, Ford 9-inch rear, power front discs | Power front disc brakes introduced, the major running change of the late first generation |
| 1977 | 200 I6; 302 V8 | Dana 44 front, Ford 9-inch rear, power front discs | Final year of the compact first-generation Bronco before the full-size 1978 redesign |
Engines and drivetrain
The first-generation Ford Bronco (1966-1977) started with a 170-cubic-inch inline-six as the base engine, with the 289-cubic-inch V8 added as an option during the 1966 model year. The 302-cubic-inch Windsor V8 replaced the 289 for 1969, and the base six grew from 170 to 200 cubic inches for the 1973 model year. A 3-speed manual was standard for most of the run, and both the C4 3-speed automatic transmission and power steering became available for 1973. Power was sent through the transmission to a gear-driven Dana 20 transfer case, mounted to the gearbox by an adapter rather than divorced, which split drive to both axles. One point of caution when comparing figures: ratings published before 1972 are SAE gross, while 1972 and later figures are SAE net, so a 302 in a 1976 Bronco shows a lower number than an earlier one even though the basic engine family is the same.
Axles and suspension
Every first-generation Bronco from 1966 to 1977 used coil springs at the front and leaf springs at the rear, an unusual layout for a 4x4 of the period and part of why the early Bronco rides and articulates the way it does. The front axle was a Dana 30 from 1966 through 1970, then Ford introduced the stronger Dana 44 front axle as a running change during the 1971 model year and kept it through the end of the run, so some early-build 1971 trucks can still carry the Dana 30. The rear axle was the Ford 9-inch for the entire generation, so the 9-inch is not a late addition; it was there from the first 1966 trucks.
When did the early Bronco get disc brakes?
The first-generation Ford Bronco used front drum brakes from 1966 through 1975. Power front disc brakes were introduced for the 1976 model year and carried into the final 1977 model year. This means a 1976 or 1977 early Bronco stops noticeably better than a drum-braked 1966 through 1975 truck, and it is one of the clearest ways to tell a late first-generation Bronco apart mechanically.
Body styles and trims
The first-generation Bronco was sold under three body codes on the same 92-inch wheelbase. The U13 was the open roadster with no doors and no fixed top, the most stripped-down version, offered only from 1966 through 1968. The U14 was the half-cab pickup with an enclosed cab and a short pickup bed, offered from 1966 through 1972, and the U15 was the full-length wagon with a removable hardtop. The roadster was dropped after 1968 and the half-cab after 1972, leaving the U15 wagon as the only body style from 1973 through the 1977 finish. Ford offered factory and dealer options including the Sport appearance and trim package (introduced for 1967), larger engines, and a variety of axle ratios. Beginning around 1971 and continuing into 1975, Ford also offered the Bill Stroppe-built Baja Bronco, a limited factory-blessed package of roughly 650 units honoring Stroppe's Baja 1000 racing Broncos, fitted with an automatic transmission, power steering, fender flares, dual shocks, and a padded roll bar in a distinctive red, white, blue, and black paint scheme; it is the truck the 2025 Stroppe Edition honors.
What to know when buying a first-generation Bronco
Because the first-generation Bronco (1966-1977) used a body-on-frame design with steel body panels over a separate frame, rust is the dominant concern: check the floors, rear quarters, the rocker areas, and the frame itself, especially around the rear spring hangers. Confirm which front axle is fitted, since a 1971-1977 truck should have the Dana 44 and a 1966-1970 truck the Dana 30, and mismatches indicate a swap. The 1976-1977 trucks bring factory power front discs, while earlier trucks have front drums that many owners convert. The open U13 roadster (1966-1968) is the rarest body and commands the most attention, so verify the body code on the data plate rather than trusting appearance alone.
Frequently asked questions
When did the Ford Bronco get the Dana 44 front axle?
The first-generation Ford Bronco received the heavier-duty Dana 44 front axle as a running change during the 1971 model year, replacing the Dana 30 used from 1966 through 1970. Because it arrived as a running change, some early-build 1971 Broncos can still carry the Dana 30, and the Dana 44 continued through the end of the generation in 1977.
What rear axle does the first-generation Bronco use?
The first-generation Ford Bronco used the Ford 9-inch rear axle for every model year from 1966 through 1977. It was not a late addition; the 9-inch was present from the original 1966 trucks all the way to the final 1977 model year.
When did the early Bronco get front disc brakes?
The first-generation Ford Bronco used front drum brakes from 1966 through 1975, then gained power front disc brakes for the 1976 model year. The 1976 and 1977 early Broncos are the only first-generation trucks with factory front discs.
What engines came in the 1966-1977 Bronco?
The first-generation Ford Bronco offered an inline-six and a V8. The six started at 170 cubic inches and later grew to 200 cubic inches, while the V8 started as the 289 and became the 302. Remember that pre-1972 outputs are quoted as SAE gross and 1972-and-later outputs as SAE net, so later figures read lower for the same engine family.
What is the difference between the U13, U14, and U15 Bronco?
On the first-generation Bronco, the U13 is the open roadster with no doors or top, offered only from 1966 through 1968; the U14 is the half-cab pickup with an enclosed cab and short bed, offered from 1966 through 1972; and the U15 is the full-length wagon with a removable hardtop, which became the only body style from 1973 through 1977. All three share the same 92-inch wheelbase.
Sources
- Ford factory shop manuals and parts catalogs for the 1966-1977 Bronco
- VIN and door data-plate decoding for body codes (U13, U14, U15) and axle identification
- Established early-Bronco reference works and owner registries
- Period road tests and factory specification sheets
Asked all the time
When did the Ford Bronco get the Dana 44 front axle?
The first-generation Ford Bronco received the heavier-duty Dana 44 front axle as a running change during the 1971 model year, replacing the Dana 30 used from 1966 through 1970. Because it arrived as a running change, some early-build 1971 Broncos can still carry the Dana 30, and the Dana 44 continued through the end of the generation in 1977.
What rear axle does the first-generation Bronco use?
The first-generation Ford Bronco used the Ford 9-inch rear axle for every model year from 1966 through 1977. It was not a late addition; the 9-inch was present from the original 1966 trucks all the way to the final 1977 model year.
When did the early Bronco get front disc brakes?
The first-generation Ford Bronco used front drum brakes from 1966 through 1975, then gained power front disc brakes for the 1976 model year. The 1976 and 1977 early Broncos are the only first-generation trucks with factory front discs.
What engines came in the 1966-1977 Bronco?
The first-generation Ford Bronco offered an inline-six and a V8. The six started at 170 cubic inches and later grew to 200 cubic inches, while the V8 started as the 289 and became the 302. Remember that pre-1972 outputs are quoted as SAE gross and 1972-and-later outputs as SAE net, so later figures read lower for the same engine family.
What is the difference between the U13, U14, and U15 Bronco?
On the first-generation Bronco, the U13 is the open roadster with no doors or top, offered only from 1966 through 1968; the U14 is the half-cab pickup with an enclosed cab and short bed, offered from 1966 through 1972; and the U15 is the full-length wagon with a removable hardtop, which became the only body style from 1973 through 1977. All three share the same 92-inch wheelbase.
The wall · registered 1966–1977 Broncos
Sorted by depth of documentation. Click any vehicle to open its permanent record.
Full year-by-year change log: 1966-1977 Ford Bronco
This log tracks the running and model-year changes to the first-generation Ford Bronco (1966-1977) at the level of body code, engine, drivetrain, axle, brakes, and federally driven equipment. It is assembled from Ford factory shop manuals and parts catalogs, VIN and door data-plate decoding for body codes (U13, U14, U15) and axle identification, period factory specification sheets and road tests, and established early-Bronco reference works and owner registries.
1966
- Introduced. The 1966 Ford Bronco launched as a compact body-on-frame four-wheel-drive on a 92-inch wheelbase, a new vehicle separate from Ford's full-size trucks.
- Three body codes from launch. The 1966 Bronco was sold as the U13 open roadster with no doors and no fixed top, the U14 half-cab pickup with an enclosed cab and short bed, and the U15 wagon with a removable hardtop.
- Base engine. The 1966 Bronco used a 170-cubic-inch inline-six as standard equipment.
- V8 added during the model year. The 289-cubic-inch V8 became available as an option partway through the 1966 model year (around March 1966), so early-build 1966 trucks are six-cylinder only.
- Drivetrain. The 1966 Bronco used a 3-speed manual transmission driving a gear-driven Dana 20 transfer case, which was bolted to the transmission through an adapter rather than mounted as a separate divorced case.
- Axles. The 1966 Bronco used a Dana 30 front axle and a Ford 9-inch rear axle.
- Suspension. The 1966 Bronco used coil springs at the front axle and leaf springs at the rear, a layout Ford kept for the entire generation.
- Brakes. The 1966 Bronco used drum brakes at all four wheels.
1967
- Dual-circuit master cylinder. The 1967 Bronco adopted a dual-circuit (split) brake master cylinder, part of the federal safety equipment phased in across Ford lines for 1967. Brakes remained drum at all four corners.
- Bronco Sport package debuts. The Bronco Sport appearance and trim package became available for 1967, adding bright and chrome exterior trim along with upgraded interior appointments over the base Bronco.
- Otherwise unchanged. The 1967 Bronco continued with the 170 inline-six, optional 289 V8, Dana 30 front axle, Ford 9-inch rear, and the U13, U14, and U15 body codes.
1968
- Side marker lights. The 1968 Bronco added side marker lights to meet new federal lighting rules in effect for the 1968 model year.
- Last year of the open roadster. The 1968 model year was the final year for the U13 open roadster body; the half-cab and wagon continued.
- Drivetrain unchanged. The 1968 Bronco kept the 170 inline-six, optional 289 V8, Dana 30 front axle, Ford 9-inch rear, and four-wheel drum brakes.
1969
- Roadster dropped. The 1969 Bronco range narrowed to the U14 half-cab and U15 wagon after the open roadster was discontinued.
- 302 V8 replaces the 289. The 1969 Bronco's optional V8 became the 302-cubic-inch unit in place of the 289.
- Otherwise unchanged. The 1969 Bronco kept the 170 inline-six as the base engine, the Dana 30 front axle, the Ford 9-inch rear, and four-wheel drum brakes.
1970
- Last year of the Dana 30 front axle. The 1970 model year was the final year for the Dana 30 front axle before the 1971 upgrade.
- Otherwise unchanged. The 1970 Bronco continued with the 170 inline-six, optional 302 V8, Ford 9-inch rear, four-wheel drum brakes, and the half-cab and wagon bodies.
1971
- Dana 44 front axle. The Dana 44 front axle was introduced as a running change during the 1971 model year, replacing the Dana 30, so some early-build 1971 Broncos can still carry the Dana 30. The Dana 44 continued through the end of the generation.
- Bill Stroppe Baja Bronco. Beginning around 1971, Ford offered the Bill Stroppe-built Baja Bronco, a limited factory-blessed package of roughly 650 units honoring Stroppe's Baja 1000 racing Broncos. It came with an automatic transmission, power steering, fender flares, dual shocks, and a padded roll bar, finished in a distinctive red, white, blue, and black paint scheme. The run continued into 1975, and it is the truck the 2025 Stroppe Edition honors.
- Otherwise unchanged. The 1971 Bronco kept the 170 inline-six, optional 302 V8, Ford 9-inch rear, and four-wheel drum brakes.
1972
- Power ratings move to SAE net. Published output for the 1972 Bronco reflects the industry move from SAE gross to SAE net ratings, so the same 170 six and 302 V8 read lower on paper than in prior years even where the hardware was largely unchanged.
- Last year of the U14 half-cab pickup. The 1972 model year was the final year for the U14 half-cab pickup. The U15 wagon was the only body style offered for 1973 and after.
- Otherwise unchanged. The 1972 Bronco continued with the Dana 44 front axle, Ford 9-inch rear, four-wheel drum brakes, and the half-cab and wagon bodies.
1973
- 200 six replaces the 170. The 1973 Bronco's base inline-six grew from 170 to 200 cubic inches.
- Automatic transmission available. The 1973 Bronco offered the C4 3-speed automatic transmission for the first time, alongside the standard 3-speed manual.
- Power steering available. Power steering became available as a factory option for the 1973 Bronco.
- Fuel system revisions. The dual-tank fuel selector valve moved to the dashboard for 1973, and the fuel filler was relocated higher on the rear quarter panels.
- Wagon-only body. The U15 wagon was the only body style for 1973, following the discontinuation of the U14 half-cab after 1972.
- Hardware unchanged. The 1973 Bronco kept the optional 302 V8, the Dana 44 front axle, the Ford 9-inch rear, and four-wheel drum brakes.
1974
- Seatbelt-ignition interlock standard. A federally required seatbelt-ignition interlock system was standard on the 1974 Bronco, a one-year-only federal requirement.
- Hardware unchanged. The 1974 Bronco continued as the U15 wagon with the 200 inline-six, optional 302 V8, Dana 44 front axle, Ford 9-inch rear, and four-wheel drum brakes, with no significant mechanical change for the model year.
1975
- Last year of front drum brakes. The 1975 model year was the final year the Bronco used front drum brakes before the 1976 disc-brake change.
- Catalytic converter and unleaded fuel. For 1975 the Bronco's V8 gained a catalytic converter and required unleaded fuel, with a filler-neck restrictor, in line with industry-wide 1975 emissions standards.
- Otherwise unchanged. The 1975 Bronco continued with the 200 inline-six, optional 302 V8, Dana 44 front axle, and Ford 9-inch rear.
1976
- Power front disc brakes. The 1976 Bronco introduced front disc brakes in place of the front drums used through 1975, paired with a power brake booster.
- Otherwise unchanged. The 1976 Bronco kept the 200 inline-six, optional 302 V8, Dana 44 front axle, and Ford 9-inch rear.
1977
- Final year of the compact Bronco. The 1977 model year was the last for the compact first generation before the larger 1978 redesign moved the Bronco onto the full-size F-Series platform.
- Hinged fuel-filler door. The exposed screw-on exterior fuel cap was replaced by a hinged fuel-filler door set into the body, a late first-generation detail.
- Otherwise unchanged. The 1977 Bronco carried the 200 inline-six, optional 302 V8, Dana 44 front axle, Ford 9-inch rear, and the power front disc brakes introduced for 1976.