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Easy way to tell a bad wheel bearing

18K views 40 replies 15 participants last post by  FloridaAussie 
#1 ·
Hey Guys...I recently replaced my wheel bearing and after not knowing which was bad I decided to go with some science instead!

Hopefully this will help anyone else out with a similar issue.

Background:
I've had a bad wheel bearing for the past 5 months and the sounds finally got to be too much. I tired the typical grab the wire and shake it and after trying each wheel twice i have has no luck.
Calling the dealer they said they run it on the lift and listen to each hub with a stethoscope...really??

Well being an engineer I knew that the sound was coming from the friction of the poor wheel bearing...friction develops heat.

So one day after my 60 mile commute home i took out instantly my infrared thermometer and shot each hub.
See below:

470147

Three wheels were around 122 Deg F - So That's normal

470148

153 deg F...hmmm okay i think i found it!

Replaced it
470150

man what a pain

470151

new!

And best of all the noises are gone! it feels nice to drive a silent car again!!

Anyway hope this is helpful for you guys!
 

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#2 ·
Hey nice job, and good pics !! I'm getting ready to do mine, on my 2011 Outback 2.5. Mine is the L-Rear, I've had an intermittent rumble for months now, but I think I will try your method just to confirm. I already have the OEM Subaru hub/bearing, just dragging my feet. I will definitely do it before Winter comes, and I think I'll also do my rear brakes while I'm in there. Thanks for posting, have a nice Holiday Weekend :)
 
#4 ·
Hope it helps and good luck! Mine was a pain to do, if you do it on the ground like I did a 4lb sledge hammer with a long handle worked best! and put a scissor jack under the control arm so the suspension doesn't absorb the shock :)
 
#3 ·
Thanks for the tip. So the wheels passed the wiggle test but did they all spin freely?

My OB is starting to sound like an airplane at speeds higher than 50km/h but there are no play in any wheels and they all spin smooth and free. I also have no change in noise when turning either way. I'm assuming it's a wheels bearing as it changes noise level with the speed of the car.
 
#5 ·
Yeah they all spun freely for me. Though, when I took off the rotor and spun the hub by hand i was able to feel the grainy feeling of the bad wheel bearing.

Yeah anything over 45 mph for me was humming, at first there was a change in sounds depending on the turn i made but after a while the sound was always there.
 
#7 ·
Great job Geneworld!

"So one day after my 60 mile commute home i took out instantly my infrared thermometer and shot each hub."

I've figured that on mine too, but using my hand. Your tool would make that easier and eliminate questions, (outside of a potentially sticky brake caliper), to which one was bad. I have a question since ive got a front wheel bearing going too. I've put it off since I don't have a hydrolic press. My old GL you could easily DIY by tapping it in and out.

How did you get that bearing out of the hub and a new one in?
 
#10 ·
Oh yea. I forgot that those are available too.
That would save a lot of time.
Thanks!
Yeah Just go for the whole hub assembly, I found them onlint from MOOG for only 75$ which is more than half of what the auto part stores are offering.

One thing that would have made it easier would have been a hub puller but i didn't have one, I've also seen people using one of these Here which comes in handy from what it looks like!

I even found it cheaper Here

Edit: I'm not sure why the links i post don't work, but if you google "ATD Tools Wheel Hub Removal Tool (ATD-8629)" You'll find what i'm talking about from Amazon and also from TOCBER Where i found it at over half the price
 
#11 ·
Hey Guys...I recently replaced my wheel bearing and after not knowing which was bad I decided to go with some science instead!

Hopefully this will help anyone else out with a similar issue.

Background:
I've had a bad wheel bearing for the past 5 months and the sounds finally got to be too much. I tired the typical grab the wire and shake it and after trying each wheel twice i have has no luck.
Calling the dealer they said they run it on the lift and listen to each hub with a stethoscope...really??

Well being an engineer I knew that the sound was coming from the friction of the poor wheel bearing...friction develops heat.

So one day after my 60 mile commute home i took out instantly my infrared thermometer and shot each hub.
See below:

View attachment 470147
Three wheels were around 122 Deg F - So That's normal

View attachment 470148
153 deg F...hmmm okay i think i found it!

Replaced it
View attachment 470150
man what a pain

View attachment 470151
new!

And best of all the noises are gone! it feels nice to drive a silent car again!!

Anyway hope this is helpful for you guys!
I am so happy to hear this. I just bought a 2012 Outback 3.6 Limited and the dealer is giving me all kinds of trouble. I hear a whinning noise and the rumbling feel going down the road. It is in a new dealership and they are replacing a U-joint and left rear wheel bearing, $800.00. Hope this is the right fix.
 
#15 ·
Almost the same title to the same suggestion I posted 6 years ago:

The temp gun doesn't always work so our titles might border on click-bait. LOL. Subaru wheel bearings are easiest to diagnose by ear. If you pay close enough attention you can tell which corner it is, with terrible hearing I get it right 100% of the time. I just ordered 2 Subaru front wheel bearings 30 minutes ago for two different Subarus and I have no worries about which corner is bad and I used nothing but my ears.

Very occasionally some are hard to pinpoint and no method is 100% determinate on all failure modes - these require a multi pronged approach of noise, temp, stethoscope, play.

The temp gun should be the first step as it is the simplest as it requires no tool or jacking the car up. And if you have to buy a tool you get a fun one to play with for other things too! Additionally check for play and take note if you can amplify the noise around turns at certain speeds to assist listening or check with the gun multiple times in case the style of driving didn't exacerbate the bearing failure and heat geneartion.

But honestly, with just focusing and paying closer attention most people should most of the time be able to pinpoint the corner it's making noise. If you have a "hunch" or a guess, like I did when I first started diagnosinig them, you're probably right and after you do this dozens of times you'll learn that hunch is right. Sit in both sides of the car, lean over, window up/radio off, quiet, or window down to hear external noises. Sit in the rear and do the same. Vary driving speeds and turns to see if you can amplify the noise.
 
#16 ·
The temp gun doesn't always work so our titles might border on click-bait. LOL. Subaru wheel bearings are easiest to diagnose by ear. If you pay close enough attention you can tell which corner it is, with terrible hearing I get it right 100% of the time. I just ordered 2 Subaru front wheel bearings 30 minutes ago for two different Subarus and I have no worries about which corner is bad and I used nothing but my ears.
The noise you hear from a faulty wheel bearing doesn't come from nothing though, it is added friction to the system; friction develops heat.

You're right though; no method is 100%, I've had a few different people in my car in different seats going through bendy roads and they all couldn't agree on which one it was. I was the only one with the correct suspicion before doing the heat test.

I simply took the personal opinion out of it since numbers don't lie.

But I can edit my original post saying that this might not work for everyone to not make it "click-bait"
 
#24 ·
I'll be using the Hub Shocker that you linked to. I got it off of Amazon already, I think it'll be worth the $100. YouTube videos of same are promising.

I like how you used the scissor-jack under the control arm to take the load/shock off of the suspension system.

Question; do you think a bottle-jack (with a small piece of wood maybe) would work just as well to absorb the shock of hammering ? If you had both a bottle-jack and a scissor-jack, which one do you think you'd prefer best?

Thanks :)
 
#25 ·
Oh let me know how that works for you! I am wanting to get one if i need to do another one.

I'd say both jack styles would work, any way you can hold it will greatly improve the effectiveness of the hammer hits. That's one thing that I've found missing from all the videos and tutorials I've found online. If i were to choose I'd go with the scissor style since it is a mechanical hold as opposed to a hydraulic hold.
 
#26 ·
Hey Guys...I recently replaced my wheel bearing and after not knowing which was bad I decided to go with some science instead!

Hopefully this will help anyone else out with a similar issue.

Background:
I've had a bad wheel bearing for the past 5 months and the sounds finally got to be too much. I tired the typical grab the wire and shake it and after trying each wheel twice i have has no luck.
Calling the dealer they said they run it on the lift and listen to each hub with a stethoscope...really??

Well being an engineer I knew that the sound was coming from the friction of the poor wheel bearing...friction develops heat.

So one day after my 60 mile commute home i took out instantly my infrared thermometer and shot each hub.
See below:

View attachment 470147
Three wheels were around 122 Deg F - So That's normal

View attachment 470148
153 deg F...hmmm okay i think i found it!

Replaced it
View attachment 470150
man what a pain

View attachment 470151
new!

And best of all the noises are gone! it feels nice to drive a silent car again!!

Anyway hope this is helpful for you guys!
Hey...that’s pretty darn slick....I’ll have to try that too...in the 9 years I’ve been driving the 4th Gen.....I’ve replaced all for corner bearings
 
#27 · (Edited)
Definitely a +1 on the hub shocker tool. My son did mine at his work and he hit the hub several times with a 4 lb hammer and no joy. Put the tool on and one hit with a 10 lb sledge and it was off!

Don't buy anything from www.tocber.com as it is a scam website. Seems a common scam these days is to have a website that sells stuff under the market rate. You buy it, they get the money from PayPal and then send you a stolen UPS delivery confirmation for somebody else as proof to PayPal that they delivered the item then PayPal closes your complaint and you have no recourse. UPS won't send you any documentation or tell you where the delivery confirmation was delivered.
 
#33 ·
i've done at least 5 wheel bearings across the 5 subaru's i've owned. don't think i've ever had one that i had noticeable wiggle in. i usually drive under an overpass and listen for the echo.
good idea on the temperature check. look up a FLIR One camera, you can get ones that attach to an iphone or android and they show thermal images, VERY VERY cool
 
#34 ·
UPDATE

So I had to replace my rear driver's wheel bearing this past weekend and I used the Bar!

484747


Some things to note though:
1. After hitting it with the pictured 4lb hammer for about an hour I was getting a tad annoyed. So My friend brought over a larger 6lb hammer with about a 3ft handle. After a few more hits I was still getting annoyed.

2. See that Scissor jack in there? I have it supporting the suspension...All things I've seen online never used that...So we removed it and after just one hit....POP! it came off! (See Below)

3. The bar did not come with the correct flanged nut for the car, so I had to use two of my lugs...I had to replace those with some extra i had as they got destroyed! You need M12x1.25mm flanged nuts, like this one McMaster-Carr

4. Remember REMEMBER to remove the ABS Sensor first, I need to replace mine as I forgot all about that!


484748


Hope this added info helps!
 
#36 · (Edited)
That is a great way to diagnose the bearing...better than listening with a stethoscope which does work...the friction of the bad bearing is easily heard that way...but I guess you have just officially made that method old school. :)
 
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#39 ·
I know this is an old thread but came across it researching the same problem. This guy drove on a suspected bad bearing for 5 months? Seriously?? You don't have to be an engineer to understand what extreme heat does to metal, especially when supporting the weight of a vehicle. If anyone suspects wheel bearing issues, don't drive your car. There could be catastrophic failure at any time. Q: "How long can I drive with bad bearings?" A:"Until the scene of the accident.
 
#40 ·
I'm not aware of any catastrophic failure horror stories around here but I do agree that a bad bearing should be taken seriously. From what my mechanic friend tells me, wheel bearings always give ample warning prior to failure, when they get loud enough you'll know it's time. I've had only one rear go so far and I had to wait several thousand miles before the exact location became obvious. It's a slow progression but I wouldn't have taken off on a cross country trip before sorting it out.

Seems one of our Subie experts can confirm the reliability of OE bearings:
 
#41 ·
I bought 2 Mini Coopers in 2020. They were 14 and 17 years old. Both I drove home to St. Louis where I was living at the time. One I drove back from Atlanta, the other from Colorado Springs. One made wheel bearing noises around left hand curves, the other one around right handers. One I bought from a mechanic; it's strange how some people's tolerance for dodgey stuff is higher than others.
 
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