Complete Koyo bearing, race, shim and hardware set for setting up a Ford 9-inch third member that uses the LM102910 carrier bearing race.
A Ford 9-inch that sings at cruise, clunks as you roll on and off the gas, or weeps oil around the pinion yoke is telling you the third member needs bearings. The USA Standard Gear ZK F9-A master overhaul kit is the Koyo-bearing setup package for 9-inch center sections that run the LM102910 carrier bearing race. It is a common pick for freshening the rear in a classic F-100, Bronco, Mustang, Galaxie or Fairlane, a hot rod with a narrowed 9-inch, or any build getting a ratio change where every bearing should be new.
The 9-inch is a drop-out axle: ring gear, carrier and pinion all live in a removable third member that unbolts from the front of the banjo housing, and every adjustment happens on the bench. The pinion is held in a separate pinion support by two tapered bearings, with a third straight-roller pilot bearing at the nose of the pinion that stops it from deflecting under load. The carrier spins on two tapered bearings set by threaded adjusters on each side. Because the pinion is supported at both ends, a fresh 9-inch holds its pattern well under torque, but only while all three pinion bearings and both carrier bearings are tight. This kit replaces all of them at once.
USA Standard lists these parts in the ZK F9-A:
First rule out the wheel ends. A noise that changes when you swerve usually comes from an axle shaft bearing, and the Yukon tapered axle bearing and seal kit for the 9-inch handles that job. Then check the yoke for play by hand, drain the oil and look for metal. Drop the third member onto a rotating 9-inch assembly stand and inspect the pilot bearing, the pinion support and the ring gear teeth. Our Ford 9-inch problems and rebuild cost guide lays out what to look for.
Ford built the 9-inch from 1957 to 1986 with more than one carrier bearing size, and aftermarket cases add more variations, so the vehicle alone does not tell you which kit fits. The part number stamped on the old carrier bearing race does. This kit is only for the LM102910 race. If yours reads LM501310, use the ZK F9-B kit; if it reads LM603011, use the ZK F9-C kit. Third members with a Daytona-style pinion support take a different pinion bearing set again. For the same LM102910 setup with Timken bearings and a solid spacer in place of the crush sleeve, see the Yukon YK F9-A-SPC. Send us the race number and we will confirm the match, or browse the rebuild kits collection.
| Part Number | |
| Brand | |
| Bearings | |
| Carrier Bearing Race | |
| Kit Contents | |
| Fitment | |
| Weight |
Pull the third member and read the part number stamped on the carrier bearing race or cup. Spline count and vehicle year do not reliably tell you, since Ford used several carrier bearing sizes and many cases have been swapped.
Yes. USA Standard lists the pinion pilot bearing along with the carrier and pinion bearings, races, seal, shims, crush sleeve, pinion nut, ring gear bolts, thread locker, marking compound and gasket.
This kit uses a crush sleeve, which is fine for street use. High-torque drag or off-road builds often switch to a solid spacer so preload cannot relax; the YK F9-A-SPC is the LM102910 kit built that way.
Yes. It has everything to set up a new ring and pinion. Aftermarket gears use a tighter backlash range than OEM gears, so check the chart for the gears you are installing.
No. Axle shaft bearings at the wheel ends are separate. A noise that changes in turns usually comes from there rather than the third member.
Both are tapered roller bearing makers. USA Standard kits use Koyo bearings and are the value option; Yukon kits for the same race size use Timken. Fitment is the same when the race number matches.
