Reccurent front wheel bearing failure

[SJW]

We still don't know if you're running original factory wheels, or something aftermarket. A massively different offset wheel (the metal bit - not the rubber tyre) will place extra strain on wheel bearings and steering components, which could be contributing to early failure of bearings. It's hard to imagine such wheels will kill bearings this fast, but it could be contributing.

Are you running factory size tyres, or something different? Again, not likely to be a root cause, but could be contributing, so please let us know what you have.

Are you buying genuine parts, or something aftermarket? Have all "new" bearings been the same brand, or something different each time?

Are you having the entire hub replaced, with the new bearings already installed, or are your mechanics pressing new bearings into your existing hubs?

Original pajero alloy wheels. Factory size tyres and they've done 50'000 k's around the country, and still good. Entire hub is being replaced each time, but I the kicker is I've used three different mechanics and always the same result. To my mind the fault is not the bearings, but some other part of the front end causing a failure.

[Jasonmc73]

When you do work it out be good to know for my knowledge bank.

[Scooby]

If there was something wrong with the front end that was loading up the bearings I would expect to see wear on the tires first.

Did you or your mechanics disassemble the old hubs and bearings to see what wear was going on?

Wheel bearings are robust and with 4wd tyres attached they are fairly isolated from impacts, unless you drive it like you stole it.😂

[Two Emms]

If there was something wrong with the front end that was loading up the bearings I would expect to see wear on the tires first.

X2 to this

So this leaves extreme shock loads, which i imagine you would notice, poor quality (which is unlikely from different fittings at different mechanics) or contamination of the bearings.

Its a bit of a left field idea but, during the fitting of the first set ( which we will have to assume simply "wore out" from usage) some seal, boot, grease cap? was damaged on the left one. I say only the left as its been replaced multiple times ( I've done 3 front left and 1 front right wheel bearing over less than 10k KM ) but it could be both.

If you have been in water, mud or sand since, it may be getting into the bearings.Depending on the damage,even driving in rain could see water drawn into a hot (operating temp only) bearing, washing the grease out.I would guess that the seal/cap is damaged, if it was missing, one of the mechanics would have noticed and replaced it.

Not being intimately familiar with the setup i cant help with exactly where to look for the damage, sorry

[erad]

The bearing assembly is pressed into the carrier and bolted in place. The axle then goes through and the axle nut is tightened to a considerable torque. If the hub is misaligned relative to the original fitment, tyre wear would be immediate and also you would notice the steering puling one way or the other. So even if the hub is not fitted correctly to the carrier, I still cannot see it loading the bearings excessively without you seeing tyre wear first. The only other variable is the axle nut, or as noted above, some crud getting into the bearing because of a faulty seal (which is built into the hub anyway). I would check the 'Good" bearing and see how tight the axle nut is and compare if possible to the stuffed bearing side.

[Jasonmc73]

I would just follow the instructions & check the specs

Edit: I'm completely intrigued, for the original post please do let us know how & what caused this when you do work it out.
If the specs for axial play & bearing start up torque are correct & staying that way, we know wheel is aligned, so the bearing must be as the wheel is bolted to it, your rims are not turning blue from heat,
Diffs not leaking & CV joints obviously not busted, axle punching bearing, can't be.

I'm genuinely interested why 3 sets of bearings in 100-150 hours of use, intrigued & honestly would love to know.
Feel like pulling it apart myself . I'm in no way suggesting i can do better just intrigued.

[SJW]

Thanks for all the replies, I really appreciate it. Good points about the tyres too. I'm not sure whether to go to a front end specialist or a pajero specialist next. I think the later. I'll report back if anything gets solved. Any recommendations for a mechanic in the Sydney area would be appreciated. Cheers.

[Pajshomoneroguntero]

Artarmon Automotive. I’ve been to them once so far and that was on the many recommendations on this forum. Can’t offer much else except perhaps a bad batch of bearings. I can’t recall if you were using genuine hubs with pre-installed bearings but if not that would be my next go-to. Otherwise I think it was mentioned that perhaps steering componentry may be the contributing factor however I would expect the tyres to show evidence of this first.

[SJW]

I would just follow the instructions & check the specs

Edit: I'm completely intrigued, for the original post please do let us know how & what caused this when you do work it out.
If the specs for axial play & bearing start up torque are correct & staying that way, we know wheel is aligned, so the bearing must be as the wheel is bolted to it, your rims are not turning blue from heat,
Diffs not leaking & CV joints obviously not busted, axle punching bearing, can't be.

I'm genuinely interested why 3 sets of bearings in 100-150 hours of use, intrigued & honestly would love to know.
Feel like pulling it apart myself . I'm in no way suggesting i can do better just intrigued.

And the winner is...the left drive shaft. It turns out that the driveshaft installed before we bought the car was incorrect as it was missing a 2 mm lip that stopped the driveshaft from pressing against the rubber and outer rim of the hub assembly. In the attached photo you can see the NEW shaft connected to the OLD hub assembly. The hub is blue where it was overheating due to the contact with the old shaft. You can see the new shaft has a small 2 mm space between it and the hub, which prevents this contact.

So why didn't we have a left side wheel bearing failure during our 40 thousand kilometer trip through some very rough country not long after buying the car? All done with an incorrect left drive shaft it seems. The only answer out mechanic could give was that the bearing was not tightened fully leaving a space between it and the shaft. Then when the bearing went due to age (the vehicle had 300,000k on it when we got it), a new one was installed and tightened correctly creating the contact with the shaft. This was then repeated multiple times until this new mechanic decided to further explore.

I'm not a mechanic and don't do my own work so some of the above assumptions could be wrong. I really hope they're not.

[Jasonmc73]

And the winner is...the left drive shaft.

This was then repeated multiple times until this new mechanic decided to further explore.

The new mechanic sounds like he might be a mechanic & not a parts fitter

Time will tell but there is a lot of parts fitters in Australia these days & less & less mechanics.

I bet ya when the parts fitters put it together it would have been tight as by the looks of things to turn & they still couldn't work it out................even though it was eating bearings on one side only!

The original parts fitter probably had no clue as to what axle nut tension should have been & just backed it off as it was hard to turn, hence you got 40,000k's .
Completely logical, its a plausible suggestion.

I rest my case, i'm not suggesting i could do any better & sometimes these hidden problems can be a brain twister.

[disco stu]

Glad you found the source of the problem.

Sounds like others have the same opinion of most mechanics that I do, and I strongly suspect that Jason is correct with his thought what the original mechanic did

[SJW]

The new mechanic sounds like he might be a mechanic & not a parts fitter

Time will tell but there is a lot of parts fitters in Australia these days & less & less mechanics.

I bet ya when the parts fitters put it together it would have been tight as by the looks of things to turn & they still couldn't work it out................even though it was eating bearings on one side only!

The original parts fitter probably had no clue as to what axle nut tension should have been & just backed it off as it was hard to turn, hence you got 40,000k's .
Completely logical, its a plausible suggestion.

I rest my case, i'm not suggesting i could do any better & sometimes these hidden problems can be a brain twister.

I think a lot of inner city mechanics just deal with new or newer city cars, so an old 4wd would be rare. They wouldn't even consider an incorrect drive shaft installation. It's pretty odd. Still it would have been good if someone had spotted it a few dollars back.

[Jasonmc73]

I think a lot of inner city mechanics just deal with new or newer city cars, so an old 4wd would be rare. They wouldn't even consider an incorrect drive shaft installation. It's pretty odd. Still it would have been good if someone had spotted it a few dollars back.

It is Odd, but your looking for odd when something continues to fail that doesn't generaly continue to fail.
As you say, sorts the men from the boys

[pharb]

And the winner is...the left drive shaft. It turns out that the driveshaft installed before we bought the car was incorrect as it was missing a 2 mm lip that stopped the driveshaft from pressing against the rubber and outer rim of the hub assembly. In the attached photo you can see the NEW shaft connected to the OLD hub assembly. The hub is blue where it was overheating due to the contact with the old shaft. You can see the new shaft has a small 2 mm space between it and the hub, which prevents this contact.

So why didn't we have a left side wheel bearing failure during our 40 thousand kilometer trip through some very rough country not long after buying the car? All done with an incorrect left drive shaft it seems. The only answer out mechanic could give was that the bearing was not tightened fully leaving a space between it and the shaft. Then when the bearing went due to age (the vehicle had 300,000k on it when we got it), a new one was installed and tightened correctly creating the contact with the shaft. This was then repeated multiple times until this new mechanic decided to further explore.

I'm not a mechanic and don't do my own work so some of the above assumptions could be wrong. I really hope they're not.

This doesn't completely make sense, although I suspect some of the explanation from the mechanic could of been lost in translation.

If the dust cover arrowed was in contact with the bearing shoulder it would of made noise and made the wheel hard to turn. Metal on metal always makes noise. If it was only lightly touching then the resistance and noise would of been only slight, maybe a squeak like a brake pad wear indicator and it would not of created heat, or any issue.

If the dust cover was hard enough against the bearing shoulder to create heat it would of made a mess of the dust cover and probably melted the bearing seal. All points of evidence of an issue that any mechanic would of noticed, not to mention the almighty scraping noise as you drove along.

If the bearing seal was not heat damaged then the heat signature of the bearing would of been from the manufacturing process.

I suspect, but only due to no other explanation, that if the dust shield was touching the bearing housing the previous mechanic might of backed the tension off to remove the contact which would of left the bearing with not preload on it. Without the appropriate preload on the bearing (the inner section is actually made of 2 sections) the bearing would of worn prematurely.

With no pretension at, all the bearing will fail very quickly.