Prerunner Front Wheel Bearing WHY question???

Why don’t we just ask @05Taco4x4 since I feel like he’d be the authority on these things?

 

I do not think the two races touch- I didn't measure the gap but I pushed out one of the plastic sleeves and there is a visible gap between the two races. If you look at the first picture I posted you can see a thin band of bright metal above the race and then a contact line on the hub where the other race was.

 

You may be correct, but I tend to agree with Steve, on the hundreds or more tapered roller bearings or angular contact ball bearings, never have I seen the opposing bearing inner races touch.

On plain ball bearings, when stacked, yes I have seen where they sometimes touch inner races or a shim is placed between inner races to ensure the bearing is not crushed or excessively preloaded when the retaining nut is torqued.

 

Thanks to those that posted valid info.

Did some research into what Timken suggests for bearing preloads.

If you care to read more from qualified sources, this explains a lot.

https://www.timken.com/wp-content/uploads/2016/10/5556_Bearing-Setting-Brochure-1.pdf

 

What happens if you torque the nut down to 400 pounds?

 

After thinking about this a bit (and remembering the switch over to sealed bearings in as many spots as possible) I don't think it had anything to do with making it more foolproof OR even more reliable. I think it was to limit damage from failure.
Since OP brought this up I suppose he had experience with the old open cage bearings. So I guess you recall the welded together or cut spindles from heat failures on the side of the road that used to be common? Still do see them where boat trailers are common.
I'm not trying to stick up for the new style, although I'm not a fan of packing bearings but I think the new style gives more warning before catastrophic failure.

 

In part, some of what you mentioned seems viable. Actually, portions of several posts are viable.

Yes, pressed onto the hub, the inner bearing race has less chance to spin and destroy the hub.

After reading the Timken engineering info, it becomes apparent there are multiple options for oem design teams to offer a design aimed at greater profits and reasonable reliability.

Timken clearly states the old school methods of design that utilize manually setting bearing preload are still viable and common today.

Timken offers the oem several variations on bearing designs that do not utilize manually setting preload. These designs require the bearing manufacturer to produce high quality close tolerance parts repeatably. The human factor and human skill expertise is removed when these designs are used. In short, slap it together and go. No adjustments or skill beyond basic skills are required.

As a guideline that the old school wheel bearings were cleaned and repacked at specified intervals or when brakes were overhauled, typically, no more than 50,000 miles, getting 50,000 miles or more on these pressed together assemblies seems reasonable. With the Tacoma, most people disregard any preventative maintenance on the front wheel bearings, simply running them until failure.

The old school design caused axle damage if run to failure. So in that regard the new is better. Add to that, during replacement of these new style bearing assemblies, the human factor is somewhat removed, and after replacement, similar mileage can be expected again.

Thanks to those that posted viable comments. Plan to order new bearings, seals, etc and replace both side bearings before they fail. 70,000 miles seems fair without any regreasing.

 

You can grease new bearings. laughs, hate to throw another wrench but the 'sealed'bearings have shit grease in them and can be upgraded.

 

Good info in here, not going to respond to your tag in that other thread

 

Never wanted you to, just directing him to a reputable source to buy assemblies.

 

A little unsolicited advice... If you never take anything personal, you'll never be offended.