I just replaced both of the front wheel bearings on my 04 4WD with 95K miles. For the record, this can be done without removing the front axles, and without a press. Here are the tools you should definitely have on hand: breaker bar, needle nose pliers, large pry bar, BFH, assortment of metric sockets (deep well and standard, 14mm, 17mm, 19mm, 21mm, 22mm and that might not be all of them), ĹĒ torque wrench, penetrating oil, large pittman arm puller or ďpickle forkĒ (either works but I recommend the puller), assorted metric wrenches, 32mm axle nut socket, and assorted wood blocks. In addition, I highly recommend a strong impact wrench and a propane or MAPP torch.
I didnít see a how-to here on the forum so here goes:
1. Jack up frame and support with jack stand, remove front wheel, brake caliper, torque plate, sway bar link, and separate upper control arm from spindle. There are plenty of existing how-to articles for these steps.
2. Remove tie rod end from spindle: remove cotter pin, loosen the nut until it sits just beneath the top threads of the bolt, and give it a sharp rap with your BFH. It should un-seat pretty easily. If youíve got a small pittman arm puller you could use that too.
3. Disconnect wheel speed sensor wiring harness. Believe it or not, this was probably the most frustrating part of the job for me. My theory is that microscopic grit accumulates in all the tiny cavities in and around the harness interface, which after 95K miles makes it incredibly difficult to pull apart. That or I just really suck at separating wiring harnesses. Once you get it, unclip the wire from all the securing points and let it hang out of the way.
4. Remove the bolt that goes through the bottom of the spindle (it secures the ball joint to the spindle). Itís in there pretty snug so youíll probably have to pop it out with a hammer and a punch after you remove the nut.
5. Remove axle cotter pin and axle nut. Like you did with the tie rod end, give the axle a sharp BFH rap when the nut is almost off of the shaft. This should separate the axle from the hub.
6. Since you already separated the upper control arm, you should now be able to grab the top of the spindle and move it all around pretty freely. Itís still seated on the ball joint shaft and the axle is still going through it so itís not going anywhere yet. Your goal is to move the top of the spindle as far away from the wheel well as possible. As youíre doing that, pull (by hand) the axle out of the hub. Youíve got to pull it pretty hard and the spindle has to be swung outward to the correct angle at the same time. This is not really that hard to do, just hard to explain.
7. At this point you need to temporarily secure the top of the spindle somehow (temporarily re-connect it to the UCA or have an assistant hold on to it, because youíre about to un-seat the ball joint and the spindle will drop to the ground if unsupported). Un-seat the spindle from the ball joint. You can either do this with a pickle fork separator or a pittman arm puller. I used both methods (one on each side of the truck), and I prefer the puller since itís a little easier to control and it wonít trash your ball joint boot. Note to reader Ė if youíre considering changing out your ball joints, nowís a great time for it.
8. The whole spindle should now be ready to come off the truck. Set it on the floor with the lugnuts facing down and spray the backside of the spindle liberally with penetrating oil. You should soak the three bolts that secure the hub to the spindle, and also soak the circumference of the hub where it joins the spindle.
9. The three hub nuts are torqued tight from the factory (155 ft-lbs, I believe) and they also have high strength thread lock applied. Combine those two factors with 95K miles and youíve got a job ahead of you. My impact wrench is a BEAST and it didnít have enough *** to remove them by itself. I had to heat the bolts up with a propane torch, one at a time, and simultaneously hit them with the impact. This is actually the most satisfying part of the job IMO.
10. With those three bolts removed, you now need to un-seat the hub from the spindle. I did this by building a cradle out of two stacks of wooden blocks and then setting the spindle lugnuts-down on the blocks (see pic). Pay attention to how the brake dust shield is aligned because youíll want to reinstall it the same way later. Once youíve got the spindle securely supported, hit the **** out of the bearing with your BFH. On the first wheel I was being kind of a **** about it so it took quite a few whacks to get it out. On the second wheel my confidence was up so two solid hits and it was out. Donít worry about damaging the bearing since youíre tossing it anyway.
11. Toss out your old bearing and inspect the mating surface inside the spindle. If thereís any irregularity, sand it a little until itís smooth. Then oil or grease it a little all the way around.
12. Set the new axle hub lugnuts-down on a sheet of plywood (to protect the threads) and gently lower the spindle down on to it. Take your time and make sure the three bolt holes line up just right. You should be able to seat it just a little bit by hand, without any tools.
13. Now insert the three hub bolts and tighten them by hand until they begin to snug. If youíre re-using your old bolts, apply some high strength thread lock to the threads beforehand. If you bought new OEM ones like me, they already have thread lock on them. With your socket, tighten each one a little at a time. Just keep going around in a circle, giving each bolt a couple of turns at a time. You want to keep the spindle fairly parallel to the hub so it doesnít bind up or distort. This is easy to do if you resist the urge to tighten each bolt a whole bunch at a time. Once the hub is fully seated into the spindle, torque each one to 155 ft-lbs (bracing the spindle while you torque them might give you a workout if you donít have a large prybar and an assistant).
14. The spindle is now ready for re-installation. Re-seat the spindle on the ball joint stud. I did this by supporting the spindle with a floor jack and wiggling it a little on the ball joint as I slowly raised the jack. Donít over-seat it or the through-bolt wonít be able to get through the spindle. Just look through the hole in the spindle while you raise it with the jack and youíll see what I mean.
15. If you got this far, then the rest of the re-installation is a breeze, just follow the reverse order of the above steps.
I got my bearing/hub assemblies from Rock Auto. I got the Timkens which is the same brand Nissan used for OEM.
They come with new Bosch wheel speed sensors pre-installed. I also bought new OEM hub-to-spindle bolts, but after removing the originals I realized they still looked decent and might have been suitable for re-use. Re-use at your own risk; I was little skeptical of doing so after putting them through the torch/impact wrench cycle. You might also need some new cotter pins for your axle nut and tie rod end. If youíre a non-mechanic like me then I would budget a whole day for both wheels. If youíre super handy and it all goes well, then maybe just a few hours. Good luck.