Most modern production vehicles are not equipped with locking/selectable hubs, but rather the axle shaft is mechanically connected to the wheel hub. This type of non-locking hub does have some benefits. It is simple, virtually maintenance free, and is often lighter than locking hubs. However, these non-locking hubs do have several down falls. Their maintenance free design makes the wheel bearings/hub assembly non-serviceable in most cases, which means the whole unit must be replaced if the wheel bearings become loose or worn out. Additionally, to replace original equipment hub assemblies you are going to be out several hundred dollars. The mechanical connection also causes wear on the drivetrain parts because the axle shafts are constantly turning, which wears out u-joints, differential bearings, ring and pinion, and transfer case bearings.
Alternatively, locking hubs allow you to connect and disconnect the axle shaft from the wheel hub, by typically rotating a knob. Locking hubs do have a few downfalls. They are more complex than non-locking hubs, are not quite as strong, and are heavier (because they have more parts). In our opinion, their benefits far outweigh the few downfalls previously mentioned. Locking hubs, while unlocked, increase fuel mileage, because the only thing turning is the bearings and the wheel hub. While unlocked, they also decrease wear on drivetrain parts that would be turning constantly with non-locking hubs. Additionally, locking hubs make the vehicle more streetable and allow you to run an aggressive traction device in the front end (such as a locker) without feeling the effects on the street, because the hubs can be unlocked.
Another benefit is that if you break an axle or u-joint on one side, and are unable to fix it where you are, you can unlock the hub on that side and it would minimize the collateral damage from the broken parts. Having locking hubs would also give you a 2-wheel-drive low range. By putting the vehicle in 4low and not locking the hubs, you are able to pull or push things in a controlled manner. Additionally, it is nice for cruising slow on backcountry roads without having the feedback feeling you would normally experience in the steering wheel while in 4low. Finally, a locking hub kit, such as the Spin-Free kit by Yukon Gear and Axle, has serviceable parts. So, if something wears out or needs attention the parts can be maintained or replaced as needed, not as an assembly, which in the long run saves you money.
In this article, we are going to give an installation overview of a Yukon Spin-Free kit on a 98 Jeep TJ. The Yukon kit that we are installing is part #: YA WU-08.
These kits have applications for many models and this installation would be nearly identical on most applications. We chose to install the kit that uses the bigger Hardcore Yukon hubs. This kit does change the wheel bolt pattern from 5 on 4 ½” to 5 on 5 ½”. There is also a kit that uses smaller, not as strong hubs, and does not change the bolt pattern, it is part #: YA WU-07.
We started by painting the non-wear surfaces of the brake rotors. While the rotors were drying we drove the races into the wheel bearing hubs. There are inner and outer races; the inner races are with the bearings with the bigger hole in the center for the spindle. After the rotors were dry, we pressed the wheel studs through the rotors into the bearing hubs.We then minimally clearanced the axle yokes to make sure the yokes do not collide against each other and limit the steering angle. The dust shields were pressed onto the clearance stubs (included in the kit). The Spicer u-joints were installed connecting the stubs to the inner shafts. We chose to upgrade the inner axles with 4340 Yukon shafts at this time. Next, the spindle seals, V-rings, and thrust washers were prepped by applying a light coat of grease on them.The v-ring was installed on the dust shield that was pressed onto the axle. Then the thrust washer was placed on the end of the stub with a beveled inside edge on first and slid down onto the flat surface. We chose to paint the mounting surface of the spindles to reduce corrosion. The spindle seal was placed into the back of the spindle and the axles were placed in their correct sides.The spindle was slid into place, over the stub shaft. Then the spindle was bolted into place and torqued to the correct spec. It is important to use the correct length bolts to mount the spindle since this kit utilizes the factory hub assembly bolts. Most factory bolts have a starter tip and it will be necessary to cut this tip off, if your bolts have it. Either way, check for clearance.Next the wheel bearings were packed, the inner bearings were dropped into their races, and the hub seals were driven in flush with the end of the hub. Finally, the bearing hubs were turned over and the outer bearings were dropped into the races.The bearing hubs were then slid onto the spindles. Spindle nuts/washers must go on in a certain order. Starting with the nut with a locking pin, next the locking washer, and then the jam nut. These nuts are tightened with a hub socket (tightening procedure is found in Yukon installation instructions); there are several styles that can be found at local parts stores. After the nut with the pin was tightened correctly, the locking washer was installed. Make sure the locking washer slides into the spindle groove and the pin on the nut that is installed first is lined up and poking through a hole on the washer. Finally, install the jam nut and tighten to spec.As for the hub installation, we first started by applying a coat of grease on the internal splines of the hub. Then, the spring retainer was installed over the spindle nuts, against the wheel bearings. The spring was installed with the larger side inward. The spacer was lightly greased and slipped over the end of the axle. Next, the driver and couplers were coated with grease on all surfaces, meshed together, and slid into the wheel hub. Lastly, the snap ring was installed on the end of the axle shaft to retain the driver and coupler.Finishing up the hub installation, the cam spacer was slid in behind the retainer plate. The cam spacer and retainer plate were lightly coated with grease and slid into the hub, which was retained with a snap ring. Next, the nylon washers were installed on the lockout bolts and a small drop of threadlock was applied. The hub was aligned with the cam spacer and the allen bolts were started. Finally, the bolts were torqued to 22 in-lbs. The brake calipers were installed and fit just like the originals.
Sources:
Yukon Gear and Axle
10411 Airport Road
Everett, WA 98204
888.905.5044
www.yukongear.com
Parts Used:
Spin-Free Kit: YA WU-08
Front Inner Left: YA D73898-1X
Front Inner Right: YA-W38875
