Front wheel bearing and hub assembly ?

also are your black hub caps in good shape, moisture could also get into there if there isn’t a proper seal around them. I know I dented mine taking it off and soon after I had a wheel bearing go bad

 

Both very good questions, and I will have to ask my trusted mechanic what condition the existing dust seals were in, as I don't believe he replaced them this time around. Unfortunately the previous Toyota warranty replacements are a bit of a mystery as to what they did. I will investigate the return. Thanks for the input, greatly appreciate it!

 

Yes let us know the outcome, they are pretty easy to bend up, I could imagine with the rust you got there would make it even easier as the caps would be harder to remove. Luckily new OEM ones can be had for 17$ a side from eBay

 

What does the front side of the hub look like?

 

Also remember the ABS sensor has an o-ring on it and also lets water into the bearing cavity if its not sealed.

 

A few more pics of the failed bearing, as well as a look at the right front assembly with the dust cover removed, for a comparison. Some surface corrosion appears on the spline area. There was a puncture hole in the outer dust cap on the left side, likely someone drove a tool through it to get it off at some stage. All sealed up on both sides now.

From various threads I've read it seems the main seal is the weakness (CV interface) then water and other road gunk just works it's way into the bearing. I realize the dirty winter conditions we experience are tough on these trucks, but replacing wheel bearings every 40-50k miles seems like a poor seal design or maybe installation method (e.g. use more or a different grease), if that is the problem?

Any other theories would be welcomed, as I really hope this isn't a repeat offender.







Passenger (right) side

 

The dust seal on the CV doesn’t look new. While looks can be deceiving it looks pretty rough.
The seal on the CV axle itself is usually the one that never gets changed. Mostly because it can be difficult to replace with the cv still in the truck. Which most people leave it in the truck when doing the hubs (including me).

If it were me, it definitely replace the seal on the back side of the spindle.
And if at all possible I’d try to replace the one on the CV if you can.
You have 3 option, 1- Try to install it while in the truck. 2. Pull the axle and install 3. Buy a new axle.
If 2 or 3 is your pick, you might as well do the axle seal on the diff.
Then run a thin bead of RTV on the inside edge of the front dust cover.

Here’s where you have to make a judgment call, if you really want to hit all areas you might pull the ABS Sensor and see how the o-ring on it is. I might consider even running a VERY thin coat of rtv on the mating surface. DO NOT GET IT ON THE SENSOR ITSELF. If the sensor feels like it’s stuck.. STOP. Don’t risk breaking it off. You might run a bead around the sensor edges the best you can and call it good. My o-rings looked good. I lubed them lightly and reinstalled them.

Personally, I don’t think the ABS Sensor is your problem.
I’m going with dust seals.

See here for the dust seals
https://www.tacomaworld.com/threads/wheel-bearing-seal-and-cv-dust-seal-install-tip.460019/

 

Great suggestions and tips. You can't beat experience.
I lightly lubed the assembly and axle thread inside those outer dust caps (on both left and right), and did put a bead of RTV around the flange (good advice from my 73 year old Dad - my first trusted mechanic), so at least that side will be sealed. I will have to ask my mechanic on Monday what the inner seal condition was like when removed as I didn't see it, and assume it was replaced with a new one that typically comes with the Dorman assembly from NAPA.

I'll report back with any new findings, but thank you for your input!

 

Definitely not a new CV dust seal. Even up here corrosion doesn't happen that fast.

Is the inner dust seal on the hub what I can see against the CV dust seal? Doesn't look too new either. Too many questions for a Sunday night, sorry.

 

The rusty one is the outer seal.
The outer kind of slide over the inner.
The inner one is in the spindle on the back side.

The outer turns with the cv axle.
The inner inner stays in fixed in the spindle.

 

Thank you for your insight and advice @TnShooter and @Eastkat808.

After a little more reading and a discussion with my mechanic that replaced the latest assembly (including the inner dust seal) I feel I have spent enough time to understand the issue. What did I learnt from all this? The dust seals are as the name implies, to reduce dust entry, and not to stop water and other good stuff that our trucks my experience (on and off road). The reality (I am now accepting) is that it is the actual bearing seals/shields that do all the work to prevent premature wear/failures, and these hub assemblies are consumables like tires. My mechanic said that in his experience (30+ years working on trucks that see a lot of abuse) it is highly variable how long these modern wheel bearings will last. He's seen some fail at less than 25k miles, while others can go >125k miles (lots of variables at play).

I did a bit more reading to try to understand if different bearing/hub assembly manufacturers have different quality seal/shield designs that would justify buying a higher priced unit, but it seems the seals used are all relatively basic, when compared with what I have seen on higher end bearings for harsh/dirty service conditions (e.g. dirt bike and mountain bikes), so I guess this falls into the category of 'planned obsolescence'. I'm sure higher end bearings may have better overall quality specs/tolerances etc. that justifies their price. Anyway, a couple of final pics here from my post-mortem, if anyone else ever thinks of going down this rabbit hole. I've also included some graphics and descriptions from the SKF website on the seal/shield designs. From this I assume the shield in the NSK 54KWH01J bearing/hub assembly I just had replaced is a non-contact design (on the inner race/ring) based on the absence of any elastomer material (i.e. seal) on that side of the shield, as seen in the pic of the cleaned shield. This may be by design to reduce friction/heat in this application, but seems likes a likely point of dirt ingress when you see how much dirt was packed against the shield when the assembly was removed.

Lesson learned: Always listen to your Father, as I could have spent my time on something I can influence if I had listened when he said "you're not in the business of fixing Toyota's design issues".

Anyway, onward and upward.