Yukon Gear Tapered Axle Bearing and Seal Kit / 3.150in OD / For 9in Ford
A Ford 9-inch rear that growls louder as speed rises, leaks gear oil onto the brake shoes, or lets the axle shaft clunk in and out has a worn axle bearing or seal. This Yukon Gear and Axle kit, part number AK SET20, replaces the bearing and seal at one wheel. It is the tapered roller bearing known in the trade as a Set 20: 3.150 in outside diameter, 1.562 in bore. It is the size used in large-bearing 9-inch housings found under 1974-1986 Ford trucks, Torinos, Thunderbirds and many street and off-road builds.
The 9-inch is a semi-float axle. Each axle shaft carries the weight of its corner of the vehicle through one bearing pressed onto the shaft near the flange. A bolted retainer plate at the housing end keeps the shaft in place, so the 9-inch needs no C-clips. In a tapered-bearing housing, the cone and rollers ride in a cup seated in the housing end. The tapered design takes both the vertical load and the side thrust from cornering. The seal keeps gear oil in the tube and out of the brakes. Ford parts specialists list the Set 20 pair as a U399A cone in a U365L cup.
Bearing noise follows road speed. Ring and pinion whine changes with throttle, getting louder on acceleration or on coast. If the noise changes on and off the throttle, the gear set or pinion bearings are the problem. In that case, the Yukon 9-inch master overhaul kit is the right part, not this one.
Lift the axle, disconnect the driveshaft and spin each wheel by hand while you listen at the housing end. Then grab the tire at the top and bottom and rock it to feel for play. Pull the drum and look for oil on the shoes. Wet shoes mean the seal has already let go, and the shoes should be replaced along with the bearing. Before ordering, measure the bore of the housing end and the bearing journal on the axle shaft.
The kit fits Ford 9-inch housings with large-bearing ends that use a 3.150 in tapered bearing. Catalog applications include the 1974-1983 F-100, 1975-1986 F-150, 1978-1986 Bronco, 1974-1983 E-100 and 1979-1988 E-150 Econoline, 1974-1976 Gran Torino, 1974-1979 Ranchero, LTD and Thunderbird, 1974-1979 Mercury Cougar and 1974-1977 Lincoln Continental. It does not fit small-bearing housing ends. One caution from the Bronco crowd: early Bronco axles swapped into Torino-style large-bearing ends can have a 1.53 in journal, which is too small for this 1.562 in bore. Measure first, or send us the axle number and your year. Find more 9-inch hard parts in our rebuild kits category.
| Brand | Yukon Gear & Axle |
| Part number | AK SET20 |
| Fits | Yukon Gear Tapered Axle Bearing and Seal Kit / 3.150in OD / For 9in Ford |
| Type | Bearings |
| Condition | New |
| Ships | Same business day (in stock), from the USA |
| Warranty | 1-year |
No. Yukon lists it as servicing one side: one tapered axle bearing and one seal. Order two kits to do both ends.
No. It needs a large-bearing housing end that takes a 3.150 in OD tapered bearing. Small-bearing ends use a smaller bearing and will not accept it.
Measure first. The bearing bore is 1.562 in. Owners swapping to Torino-style large-bearing ends have found stock early Bronco shafts measure about 1.53 in at the bearing journal, which is too small for this bearing.
Yukon describes the kit as bearing and seal. Plan on a matching press-fit retaining collar if you are cutting the old one off, because a removed collar should never be reused.
Axle bearing noise follows road speed and changes with cornering load. Gear whine changes when you go on and off the throttle. Spin each wheel by hand with the driveshaft disconnected to check the bearing directly.
