i'd noticed a very slight wobble from the front end of '87 #2 over the last month or so. thought it might be the front wheel bearings; probably a little loose. today was a good day to investigate.

'87 4runner #2 still has its factory aisin auto-locking front hubs. while i prefer the aisin manuals (and installed them on '87 #1 and have a set for #2 and a spare set), the auto-hubs are actually a bit easier to get into, whether to adjust the bearings or to do an inspection/repack. jack one side of the front, pull the wheel. remove the six allen-head screws from the hub cover, and gently remove the cover (to preserve the gasket). next, remove the 12mm bolt from the end of the axle stub.


the locking hub cover and the six 6mm allen head bolts


so, i'm showing the "process" on some spare parts, because i didn't take pictures when doing the work...this is the locking hub cover, with the hub body below it


hub cover removed. on the spindle installed, you'd see the end of the stub axle and the "gold" 12mm bolt in the center here. remove the bolt.

now it's time to pull the hub body, so the 6 nuts/cones/washers need to be removed (also 12mm). loosen the nuts to the ends of the hub studs, then use a large drift and medium hammer to smack the ends of the studs/nuts. the percussion/shock will eventually cause the cones to come free of their seat in the hub recesses (hopefully without deforming the nut or the stud threads). remove the nuts/washers/cones, and then the locking hub body should come off. once off, the snap ring on the stub axle needs to be pried off - i use a medium flat blade screwdriver - it isn't difficult, just needs some patience. next pry off the large snap ring on the outer edge of the locking hub brake mechanism. same thing, it's easy, just need patience to get it over the groove and off.


the recess in the hub body where the cone washers seat and the wheel hub studs protrude. the locking hub body is secured to the wheel hub via the cone washers with the studs running through them, and then a lockwasher and nut (12mm) on each of the six


the snap ring that holds the brake portion of the locking hub system to the stub axle. use a small flat-blade screwdriver to pry this off of the stub axle


this is what you'll see when the locking hub body is removed. this brake assembly rests within the wheel hub. imagine that the stub axle and spindle shaft are protruding through the center. you have removed the stub axle snap ring. note the snap ring/lock ring still installed around the brake assembly, and the threads of the bearing retainer nut visible (the retainer threads onto the spindle shaft)


the snap ring/lock ring that holds the brake band mechanism within the bearing retainer lock plate.

after the ring is off, remove the brake spring assembly - a wire encased in a plastic (or bakelite?) piece. be careful when removing the unit, the plastic is easy to break. just gently pry back and forth, it will come out. now the lock ring is exposed, and to remove it, use a torx head to remove the three small set screws. the ring should come off - along with a washer the fits over the stub axle splines. the hex nut that retains the bearings is now right there.


another view with the lock ring/snap ring still installed. this is the lock plate, brake spring, brake spring cover, and below is the 54mm wheel bearing nut, with threads visible


the brake spring assembly, encased by plastic/bakelite. it is two pieces. this is the "bottom" side, with one piece of the plastic removed.


the brake spring, removed from the plastic case - i didn't remove this during my bearing adjustment, just showing what it looks like


this is what happens to the plastic/bakelite brake spring cover if you aren't careful when prying the assembly up out of the lock plate.


with the brake spring assembly out of the way, the lock plate can be seen. the washer in the center can now be removed, too. again, picture the stub shaft and spindle shaft protruding through the center. the serrations on the washer allow it to slide onto the stub shaft splines.


one of the three torx head screws that hold the 54mm bearing retainer nut in place by securing it to this lock plate. only three holes will align at once to mate the two. they have offset alignements to allow for differing load needed to set to spec. there are "three sets" of 3 holes.


one of the three torx head screws


this washer is held in place by the smaller snap ring that rides in a groove on the axle stub shaft. it can be removed when the snap ring is removed, but it is easier to get to once the brake assembly is removed


the lock plate. note the tab on the inner circumference. that tab rides in the slot in the spindle shaft. the slot is at the 12 o'clock position from the factory


another view to show the small tab


the 54mm wheel bearing retainer. this is the side that faces out. the torx screws attach to three of the holes, with an unused hole between each.


the back side of the bearing retainer nut. this flat side rides against the outer wheel bearing (well, it touches it, they don't move relative to one another when installed) note the threads - these mate with the threads on the outer surface of the spindle shaft. note that there are three snapped torx head screws in this one - someone put them on too tight and they couldn't get them unstuck without breaking the heads off

because i serviced the wheel bearings last year, i was only checking to see about the bearings and whether they needed adjustment. i used my 54mm nut socket, and the nut easily loosened without a ratchet (so the bearings were probably a bit loose). i used a torque wrench and the 54mm socket to tighten the bearing nut to 43 ft-lbs. rotate the rotor/hub assembly back and forth a few times, then loosen the hub nut again until it can be turned by hand. now use the torque wrench to tighten again, this time to 18 ft-lbs. after torquing, tighten the nut the minimum needed to have either a "flat" or a "point" directly above the spindle groove.

set the three-screw lock ring in place, and if three holes align, insert the 3 torx screws. if no holes align, remove the lock ring, and tighten the bearing nut a bit, the minimum needed, to get three holes to align. check, etc, repeat if necessary. once three holes align on the bearing nut with the holes in the lock ring, insert the torx screws. add the stub spline washer, and the stub snap-ring. insert the plastic/spring brake assembly into the lock ring grooves. once seated properly, add the outer snap-ring.

align the locking hub lock mechanism by centering the tangs on the hub with the two ends of the spring in the brake assembly (encased with plastic/bakelite). if the hub body seats correctly, add the 12mm axle stub bolt. then insert the six cones/washers/nuts that secure the locking hub body to the wheel hub. torque to 23 ft-lbs. almost done. replace the locking hub cover & gasket, and attach the 6 allen head screws (6mm). do not over-tighten these.


the underside of the outer locking hub body. note the alignment here. the knockout pin recesses noted by the FSM are visible at 12 and 6 o'clock. the hub engagement parts are aligned at 12 o'clock, with the tab centered in the gap. note that the locking hub inner mechanism is damaged, probably from improper installation (didn't align the gaps correctly). it was this way when i first removed it from this 4runner. i had a good spare, and installed that.


the spring ends in the brake assembly. these two ends will fit in the gap shown in the above photo, thus the need to align the gap properly


the brake assembly as it would fit - note the spring ends in the pair of gaps, with the tab in the middle


this is how it all fits together "inside" where you can't see it. the wheel bearings are towards the viewer


another angle - note the tab on the lock ring. this rides in a groove on the spindle, and will be at 12 o'clock. the knockout pins are aligned the same, although from this view, 12 o'clock is at the bottom side of the picture


with the wheel bearing retainer nut, flat side toward the bearings...




stick the wheel/tire back on, and give it a test drive. i did both sides in 2 hours, and the test drive showed that the very slight wobble is gone.