Yukon Gear Master Overhaul Kit For Ford 9in Lm501310 Diff
A Ford 9-inch that whines on the highway, clunks on and off the throttle, or drips oil from the pinion yoke is telling you the bearings in the third member are worn. Whether it is the original axle in a 1960s Galaxie, F-100 or early Bronco, or a 9-inch you are freshening for a street rod build, the Yukon Gear & Axle YK F9-B master overhaul kit replaces every bearing and seal in the drop-out center section. This version is built for 9-inch carriers that use the LM501310 carrier bearing race, and it comes with Timken bearings and races.
The 9-inch is a drop-out design: the whole gear set, carrier and pinion support come out of the housing as one third member, so the rebuild happens on the bench. Its pinion is straddle-mounted, held by two tapered bearings in the pinion support plus a small pilot bearing at the nose of the pinion inside the case. That third bearing is a big part of why the 9-inch is so strong under load. The carrier rides on two tapered side bearings, and on this axle carrier preload and backlash are set with threaded adjusters rather than shims. When any of these bearings wear, the pinion deflects and the gear mesh drifts, and you hear it.
Yukon's listed contents for the YK F9-B:
Rule out wheel bearings first: 9-inch axles use pressed-on axle bearings, and a bad one can sound like a pinion bearing. Then lift the rear, put the transmission in neutral and spin the yoke by hand. Roughness, or any in-and-out movement at the yoke, points to the pinion bearings. Pull the third member, look at the teeth and roll each carrier bearing by hand. If the gears are chipped or scored, now is the time for new gears such as the Yukon 9-inch 3.50 gear set. If the axle bearings are the problem, the Yukon 9-inch tapered axle bearing and seal kit handles that side.
This kit fits Ford 9-inch third members with LM501310 carrier bearing races. Catalog data for it lists a 1.625 in. carrier bearing journal and a non-Daytona pinion support. The 9-inch was used in Ford cars and trucks from 1957 to 1986, and Ford used more than one carrier bearing size over that run, so do not order by spline count or vehicle alone. Pull the third member and read the number stamped on the carrier bearing race, or measure the journal. If your races read LM102910, use the Yukon LM102910 kit; for LM603011 carriers there is the USA Standard LM603011 kit, and the USA Standard ZK F9-B is a lower-cost option for this same LM501310 setup. If in doubt, send us your race numbers or your year, model and VIN and we will match it. More kits are in our rebuild kits collection.
| Brand | Yukon Gear & Axle |
| Part number | YK F9-B |
| Fits | Yukon Gear Master Overhaul Kit For Ford 9in Lm501310 Diff |
| Type | Differential Overhaul Kits |
| Condition | New |
| Ships | Same business day (in stock), from the USA |
| Warranty | 1-year |
The bearing race part number is usually stamped on the face of the carrier bearing race. Pull the third member and read it, or measure the carrier journal. Catalog data lists a 1.625 in. journal for this kit.
No. Spline count is not a reliable guide to carrier bearing size on a 9-inch. Check the race number or measure the journal before ordering.
Catalog data for this kit lists the non-Daytona pinion support. If your third member has a Daytona support, confirm the pinion bearing sizes before ordering.
Yes. The YK F9-B includes the pilot bearing along with Timken carrier and pinion bearings and races, pinion seal, crush sleeve, pinion nut, shim kit, ring gear bolts, thread locker, marking compound and gasket.
Yes, if the teeth are free of chips, pitting and scoring. Keep the old pinion shim as a starting point and verify the pattern after the new bearings are in.
