Front Wheel Bearings on '97 V6 TACO 4WD 5 speed w Manual hubs

Hey guys,
A bit of help if you can. During routine off-season MTX, I just discovered a problem with my front wheel bearings on my '97 V6 TACO 4WD 5 speed w manual hubs. The shop that pressed the last set of front wheel bearings may have pressed them into the knuckle backwards. Just checked the torque on the hub nut and its fine at 203 ft/lbs. But there is still plenty of play in the hub with the wheel mounted. The bearing does not appear to have any preload at all. Last time I did it myself, I think I remember the rubber seal side of the Toyota p/n

$89 90369-54002 Bearing

90369-54002/KOYO DU5496-5 bearing should be on the inside/knuckle side with the steel portion of the bearing facing outward towards the hub. It appears to be just the opposite now. Am I correct? TIA!

 

YEP! The shop pressed the front wheel bearings into the knuckle backwards. It took me a while to find the answer in a manual or a video. This video explains the proper front wheel bearing orientation in the knuckle at 26:00. https://www.youtube.com/watch?v=Dj-2IzO9RFk

 

I pressed out the TOYOTA/KOYO front wheel bearings that were pressed into the knuckles backwards. They were practically new with only 2000 miles on them. What a waste! 1 bearing pressed out intact but the other separated leaving the bearing cone on the hub shaft. I split the cone off the hub shaft with a coal (cold) chisel without marring the hub shaft at all. 50+ years of practice splitting bearings off shafts makes it faster than pressing them off. Everything is disassembled/inspected/cleaned so the hard work is over. Will order all the new parts needed for reassembly today. Going back with new Toyota/KOYO bearings & seals. Both OEM TOYOTA seals for the knuckle are also made by KOYO. I loathe having to redo bad workmanship! And the real pisser is that I had the wheel bearing replaced simply for routine preventative MTX in preparation for retirement. Now that I am retired, the '97 TACO is off-roading in deep mud/water for 8 months/year. But since retirement, I have the time to do my own MTX whenever possible. Just hot as hell working on this project in the August heat here in MS. I thought I had finished up all the routine MTX needed on the '97 TACO a month ago. This bearing preload problem was noticed while fixing a slow leak in a front tire. Glad I found it before the bearings failed leaving me stranded somewhere off-road.

 

I have read that before and it does not appear to be correct info at least for my application. This TACO has the threaded hubs for use with the AISIN locking hubs. Installed incorrectly with the shielded/sealed side of the bearing on the same side as the internal locking nut with spacer torqued to 203 ft./lbs., there was no effective preload on the bearing at all. Unstaking the nut and retorquing to 203 ft/lbs. made no difference in bearing preload with the bearing pressed into the knuckle backwards. It may have something to do with the shield/seal on the bearing VS the unshielded side with the black seal (below). I definitely could not sleep well at night with both front tires having that much play in them.

The shielded/sealed bearing is on the left with the unshielded bearing on the right:



In the incorrect configuration on the left, the hub nut with spacer presses against the shield/seal but not directly on the bearing cone. When torqued to 203 ft./lbs, the hub nut bends the metal shield toward the bearing cone but never quite touches it. All you have actually done is put 203 ft./lbs. on the bearing race which does nothing but damage the metal shield/seal. So there is zero actual preload on the bearing cone. In the correct configuration on the right, the hub nut with spacer presses directly against the bearing cone itself putting the required preload on the bearing.

 

I just wanted to do a follow-up on my original post. If anyone claims that the front wheel bearings will work as designed when pressed into the knuckle in either direction, tell them I said they are WRONG. Anyone making such a claim will indicate that they have no idea how the bearing works or how the front knuckle is designed/engineered to prevent water from entering. I have earned this t-shirt and can tell you from experience that the front wheel bearing does not work as designed when installed backwards. When installed backwards, no preload of the bearing is possible unless you well exceed the 203 ft/lbs of torque on the hub nut and the water resistance of the knuckle is non-existent. Do it right the first time. The metal shield on the bearing goes to the outside towards the hub. The black "rubber" seal on the bearing goes to the inside of the knuckle. .02

Correct configuration of front wheel bearing with the metal shield/seal towards the hub:



The steel sleeve on top supports the inward facing bearing cone while pressing the hub into bearing. If that cone is not supported, the bearing cage will very likely be distorted or even come apart releasing the roller bearings it captures. The only support the inward facing bearing has when pressing the hub without supporting the inner cone is the metal lined rubber seal which is pressed into the bearing race. Even if you get away without supporting the cone, your bearing job will probably not last as long as it should. .02



Hub is now fully pressed into the bearing. Install the hub nut with spacer (or ABS hardware if so equipped), torque the nut to 203 ft/lbs., stake the nut, install the inner knuckle seal and you are GTG. Note: The old bearing race makes a perfect seal driver for the inner knuckle seal. After final assembly, the hub should have no play and rotate VERY smoothly with little effort. If it does not, the bearing may have been damaged while being pressed OR the bearing was pressed in BACKWARDS! Do it yourself or get it done correctly the first time so you don't have to revisit the wheel bearings for quite a while. I average about 10 years of super hard off-road service out of each front bearing set but only when done correctly.



I have heard of some very strange methods of getting the hub nut torqued to 203 ft/lbs. A dealership reportedly had 3 mechanics working on it simultaneously to get it done. Simply clamping the knuckle in a vise works very well and can be accomplished solo. If you don't have a large vise available, mounting the knuckle assembly to one of the wheels will hold it while the nut is torqued. I have done it both ways and the vice method is much easier.