Prior to the start of Phase 4 of Project X, I had one important addition that had to be made. From previous experience with a mud racing Jeep CJ 7 with auto locking hubs I learned that auto lockers and locking diffs do not go hand-in-hand. After adding a front Detroit locker to the CJ, the auto locking hubs blew apart within two weeks. Since my plan was to add an air locker to the front of my X, I knew the auto locking hubs had to go bye bye. In their place is a nice new set of MileMarker Premium manual hubs (MileMarker #0535, 90 - 96 Nissan). My hubs were purchased from Automotive Customizers.
Adding manual hubs to a late model Nissan is fairly easy. If you have ever had to repack wheel bearings (here in Florida it is a regular thing), you have covered the bases in hub installation.
6mm Allen socket (3/8 drive)
3/8 drive ratchet
Snap ring pliers
Two flat head screwdrivers
Hot knife
400 grit sandpaper
First, remove the front wheels. This is not absolutely necessary, but makes it easier to work on the front hubs. Once you have the front wheels off, remove the six 6mm Allen head bolts holding the autolocking hubs in place (figure 1).
Figure 1, Removing the six Allen bolts from the hub assenbly
Once the hub is off, use the snap ring pliers to remove the snap ring holding the fixed cam assembly in place (figure 2). More than likely you will have to use the two flat head screw drivers to remove the snap ring as you work the pliers. Be careful not to distort the snap rings. If you do, replace them. They keep your front axle in check and can cause front end damage if not properly installed.
Figure 2, The fixed cam assembly held on with a snap ring
Once you have removed the fixed cam assembly, you are ready to install the new hub body. But before you do, take notice that as you took the snap ring off, you found a second snap ring groove towards the outer edge of the axle. This is important later on. First put one 6mm allen bolt (the new one provided with the hub) through the body and place the gasket over the bolt. Hand start the first bolt just enough to hold the body in place. Once the hub body is held in place, hand start the other 5 allen bolts. Using the 3/8 drive ratchet, tighten the bolts down like you would a set of wheel lug nuts. Start on your first one, then move to the bolt directly opposite, continuing in this pattern until the body is tightened.
Figure 3, Installing the manual hub body and snap ring
Now that the body is in place, you will install the snap ring. Remember that second snap ring groove I discussed above? Well, now is when it counts. That groove is the one you will use when installing the snap ring for the new hub.
Once the snap ring is in place, you can install the front cover. This cover uses 6 allen bolts and comes with the wrench for installation and removal. Once again, use one bolt to hold the gasket in position, and hand start the bolt. Once it is started, again hand start the other 5 bolts and use the same tightening pattern as on the body. Make sure that you check hub operation by first spinning the wheel in Free setting (it should spin freely) and then try to spin it in Lock (it shouldn't spin, or will spin briefly and then a loud clack will be heard and the wheel will lock). Make sure it unlocks correctly when finished with this test procedure.
Figure 4, Installing the manual hub cover
Now that the hub is in place, you have one last thing to do if you plan on keeping your front factory center caps. You will find that they no longer fit. I used a hot knife to cut the center of the cap out and then filed off the slag and sanded it down to a neater finish using 400 grit sandpaper (figure 5).
Figure 5, Cut the centers out of the factory center caps to fit over the new hubs
Once you have cut the center caps, you can reinstall them on the rims. If you have after-market rims, this step is not necessary. You now have a set of manual locking hubs on your X/Frontier (figure 6)!
Figure 6, The hubs with center caps installed
Since adding the MM manual locking hubs on the front of my Xterra, I had an unexpected surprise. I had a gas mileage increase of about 1.5 to 2 mpg. I don't attribute this to the addition of the hubs since the auto locking hubs do exactly the same thing. I actually attribute it to the apparent failure of one of the autolocking hubs to operate properly. Under normal circumstances, there should be no change whatsoever in gas mileage with the installation of manual hubs.
Once I installed the hubs, I noticed a difference in the way the wheel felt as well as how the truck felt after I let up on the gas. In fact, the difference in steering was so dramatic that I jacked the truck up and checked the front bearings to insure they were properly tightened. Most of you won't see anything like this. But if you do, it means that there was something wrong with your autolocking hubs. The interesting thing to me is the fact that my gas mileage hasn't changed since the day I bought my truck brand new almost two years ago. This tells me that this problem was most likely delivered with the truck.
Copyright 2001, Gordon White