Rumble strips without rumble strips? Axle shaft bearing early failure warning.

IncorpoRatedX

Explorer
I'm posting this thread as a sort of PSA, after talking to a lot of the AZ crew I learned that this is a pretty rare thing to happen and none of them had experienced it. Over the last ten years I've had a handful of montero sports and full size monteros. I've only ever experienced an axle shaft bearing failure twice over the years and through the different trucks.

The first time was a 97 sport with 110k on the clock. Driving through Chicago one winter I drove over a pothole and instead of the normal thud, it was followed by what sounded like rumble strips they put in the road to warn you of stopping or tolls ahead. I continued with my drive and it happened a couple more times. Once home I started looking into it but couldn't find much, tore the hub down and inspected all the bearings, repacked them and put it back together. No change, things got worse and the rumble strip sound would come up for about 3-5 seconds after any bump I would hit.

At the time it was my passenger front wheel causing the issue. When the noise occurred the truck did not pull to one side or change the feel of the ride, just an audible sound. Initial fears had me thinking about splines being rounded off on the axle shaft, either where it engages the hub or worse; in the diff. I went over exploded views with a fine toothed comb but at the time couldn't find one showing the axle shaft, eventually i came across one in CAPS and found the part number, tore my hub back apart and pulled the knuckle off and removed the CV shaft from the hub to find the needle bearing or 'axle shaft bearing (front-outer)' it was pretty trashed, the needle bearings were jumping out of the race and binding against the next needle bearing in line, making the strange vibration sound and leaving small marks on the CV shaft. Replacing the bearing fixed it all. I also replaced the CV shaft out of concern that the marring on the shaft could create premature wear of the shaft bearing.

Now, on my 99 montero I've got the same sound happening after a front brake rebuild (including rotors) I suspect dirt got in there while I was working and is chewing up the shaft bearing on the driverside, it's just starting to make the noise and i've got an extra shaft bearing here in my parts stash so I'll be changing it soon. I'll take some pictures of the parts, but this is the bearing:

National Bearing Part number: B2012
http://www.autozone.com/drivetrain/...shaft-bearing-front/281973_0_0/?checkfit=true

nnt_b2012_p04_ang.jpg


I've checked most suppliers local to me and they all need to order the part in. Luckily when this fails it wont stop you on the road.
 

PacS14

Adventurer
Thanks for sharing the info and solution all in one spot! I hope I don't have to do it anytime soon.
 

JamesW

Adventurer
Mine had let go too, it dropped a couple of the needles when I took the hub off to change a CV, packed it the best I could, but after a few months it started a rattle while going around roundabouts, sounded a bit like a failing CV. That lasted a month before it ******** on me and gave up completely, made an noise like a the keep awake strips at the side of the motorway, Ended up changing the hub as I was passing the farm I keep my parts shogun on

It happened to GlennC from here too, I think it is a more common one for trucks from a wet environment
 

JohnnyBfromPeoria

I'm Getting Around To It
In case it wasn't stated before, the needle bearing is a non-reusable part, so if you take it out of the knuckle, you're supposed to replace it and its seal. I've never messed with them, but this is good information. Thanks IncX.

John B.
 

IncorpoRatedX

Explorer
James, Good to hear I'm not alone on this one.

Phil, thanks for the link, i wasnt sure who the OEM might be.

JB, I dont think my first truck even had a seal (probably why it failed) I'll have to dig up the seal part number. It's not the wheel seal since that's only for the wheel bearing, this would be some sort of inner axle seal or something. You mind taking a quick look in CAPS when you get a minute?
 

JohnnyBfromPeoria

I'm Getting Around To It
MB160850, near as I can tell. Or maybe it's not...

And it hasn't been CAPS for years, greenhorn. It's ASA.

John B.
 
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