Wheel bearing question. Not how, but why?

[pjw73nh]

I've seen many of the posts here re Explorers eating wheel bearings on a fairly regular and long term basis. . Mine hasn't had any go bad yet, but I do suspect one starting. When it does go, I will replace with a Timken or SKF.

My real question is, why do they go bad? Is this a crappy design from Ford? Are they under spec-ed? Just crappy OEM quality?

It seems this has been an issue for many, many years with the Explorer. Wouldn't you think they'd have come up with some kind of remedy for it by now?

Tnx

P..../NH

 

[Themightyquinn]

the OEM hub/bearing assemblies use timkin bearings so they are pretty good quality.
Plus someone in another post mentioned the importance of torquing the axle nut to spec. I think its like 180 ft-lbs.

 

[thebrakeman]

Why do bearings go bad? You mean why do some vehicles go thru bearings, while other vehicles don't?
If you were to make as many things equal as possible (like the brand, manufacturing process, and the same "type" of bearing), as well as the same driving style, etc, I think it would come down to:
-suspension geometry
-vehicle loading

Any "stock" vehicle component (like bearings, brakes, etc) will need to be sized according to somebody's standard or recommendation. For me, in the braking industry, there are many factors that go into the thickness and diameter of the rotors, and the size & type of caliper. From there, there are subtle details of design that are tweaked to make it work for the specific application. But in some cases, you could be on the limit of design.

For the bearing, perhaps they wanted to use the next stronger/larger option, but they were limited because of wheel options, or perhaps they wanted more room for the brakes, limiting space. I'm completely guessing here, but these sorts of things (when you are on the line between 2 options), can sometimes force your decision.

As far as suspension geometry, perhaps there is just more side-loading or something else involved (dynamically) that is harder on these bearings than in other applications. Such things likely contribute to how well these SUVs handle (for an SUV!). But the tradeoff is that the life is not infinite.

In the end, having to replace bearings once during ownership is not what I would consider poor designing. If you are replacing them repeatedly, that's different.

Some may ask why don't the brakes last forever? I could design a brake package that would never wear out. But it would not stop the vehicle very well, and/or it would be VERY expensive.

 

[pjw73nh]

Brake, Tnx for the reply. Yes, I guess that's what I meant. Why do some vehicles go through several bearings. Good explanation. I too am in agreement that having a bearing go at high mileage once in a cars lifetime is not too much to ask. Of the many high mileage cars I've owned, I've only done a handful of bearings, and never the same one twice.

P.../NH

 

[thebrakeman]

Right. For the same one to go within 75,000 miles or so, I would start questioning what else in the suspension is misaligned, that is causing abnormal loading on the bearing. Or perhaps one of the drivers is sliding that wheel into curbs now and then (!).

 

[Mark5767]

I had both front wheel bearings replaced in my 06 V8 XLT in Aug 2011 80k miles and now the front passenger wheel is making troubling noises again at 117k.

So less than 40k I might have another bad bearing. And the last ones were crazy expensive to replace, something like $300 apiece?

That seems like too short of a life span and the cost seems way high. Not to complain, but what's up with that?

 

[thebrakeman]

What brand? Who did the work?

If you got Timken or another quality brand, you may have a warranty still good (?). Even if it's not, it's worth a phone call. Yeah, 40k miles isn't good, and they should hear about it.

 

[Mark5767]

A Ford dealer did the work and I just got off the phone with them.

He said they provide a 1 year 12k warranty on this work so I am SOL.

Not sure of the brand. I am taking it to an independent garage tomorrow and we'll see what they say (if it's for sure a bad bearing).

Have not used this garage before so hopefully they are honest.

Thanks for the response!

 

[Tech By Trade]

Bet it wasn't torqued properly. My no-name $60 jobber bearings have 40k on them with no issues so far.

 

[Bobmbx]

A bad alignment is the biggest culprit in front bearing failure. Loose/worn steering gear, failed shocks or struts, over-size tires or just overloading the vehicle are also top suspects.

Dirt and water also play a part. If you drive a lot on dirt or off-road through water (or both) you can contaminate the bearings with a fine grit that just grinds away at the metal like jewelers rouge`.

Early failure after replacement is most likely operator error.