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Easy Wheel Bearing Diagnosis

42K views 56 replies 17 participants last post by  CNY_Dave 
#1 ·
Subaru wheel bearings often don't have traditional wheel bearing symptoms, or at least I've never seen one actually have "play" by grabbing the wheel. I've seen them have play once off the vehicle though, but that doesn't do you any good trying to diagnose insitu. I've seen enough threads asking how to confirm and having trouble verifying wheel bearings that I snapped a couple bad cell phone pic's while diagnosing one this morning in the dark.

I use a temperature gun which I mention often on forums and so far it's been 100% successful.

1. Drive the vehicle. Get it up to operating temps.
2. Aim the red dot from an infrared temperature gun as close to the bearing/hub as you can. Use the axle stub, exposed on steel wheels, or pop the center cap on aluminum wheels. Or shoot through the slots in the wheels at the rotor close to the hub/bearing and get an "average" of like 5 or so readings - noting the highs and lows. Rotor temps vary wildly depending how far from the center you are - energy dissipation and heat transfer and what not - so that's the reason for a few readings.
3. Compare that reading to the reading on the other hub bearings.
4. If there's a large difference - usually 20-50 degrees in my experience, the side reading higher is likely a failed bearing.

***This of course assumes brakes have already been ruled out - not dragging, seized, etc.

This particular vehicle had sound that wasn't noted until after snow tires were installed so it was a uncertain as to whether it was tires or wheel bearing making the growl. The noise wasn't particularly loud and I don't have stellar hearing so I wasn't even sure if it was front or back or both.

It was dark so pardon the pictures but this explains it fairly simply and looks like i've confirmed another wheel bearing.

First pic shows the passengers side at 96 degrees. Drivers side at 127 (highest).
Both rears were 74 degrees.
Looks like we have a bad drivers side bearing. This vehicle has all new brake pads, caliper boots, caliper pad clips, etc.

***Probably one of the "funnest" tools to own, can take it inside and play with it! You'll want to take temps of all sorts of things...campfires, food, kids, windows, doors, computers....

Works on any kind of bearing.
 

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#2 ·
This will help spot one getting 'tight', and those can be harder to diagnose.

I have done 3 sube bearings so far, 1 front, 2 back, when trying to figure out which front I tried the thermometer trick and the bad side was just the same as the good side.

I came off the highway after a 30 mile drive and rolled to a stop in a parking lot almost w/o using the brakes at all.

The front one was tricky, it got quiet when on the outside of the turn, the opposite the usual.
 
#6 ·
the old methods like checking for play and listening via the strut springs while turning still hold too, but Subaru's i've run across have passed those tests multiple times with a bad bearing.

they easily make 200,000 miles too, so don't worry too much about them all going out. as far as i know all of mine are original on my 212,000 mile and 180,000 mile outbacks. they do fail but only a percentage, they aren't a wear item like brakes pads or struts either so you don't have to feel like they're always on the brink of failing.
 
#7 ·
Did this again yesterday on an 02 OBW, hard to diagnose for sure and which side it was coming from. Tested temps after an extended drive:

Front passengers side was 250 degrees
Front drivers side was 200 degrees

haven't repaired it yet - but probably wheel bearing, ordering parts now.
 
#8 ·
I didn t find my fronts bad by the heat but found them to have a tiny bit of play in the /tire while jacked up. Just grab the tire at 9 and 3 or 12 and 6 and try to wiggle it. Mine had what felt like les than 1/16 to 1/8 movement but they shouldn t have any.
08 did have different bearing than previous years. Got 80+K miles on each side. Salt may have played a part?
 
#10 ·
I started a thread on the integrated wheel bearing hub failures on the 2005-9. So far two have been examined with what looks like the same type of deterioration.

http://www.subaruoutback.org/forums...s-wheel-bearings-3rd-generation-2005-9-a.html

If anyone reading this thread has also replaced one (or more) of hubs, and still has one, perhaps it could be opened to see what happened. A post with a description of the symptoms, and perhaps some photos, would be appreciated.
 
#15 ·
I just pulled a low mileage 06 but it's buried in the scrap pile somewhere. If I see later i'll try to toss it aside if it looks inspectable.


+1, there's no normal. they can easily last the life of the vehicle...they can easily fail prematurely.

there are a few that have more issues than others - but even then it's not "predictable" by any stretch of the imagination. it's not like older cars where they needed repacked every 30k or they'd fail for sure...bearings have come a long way since cars road on trailer-like wheel bearings.
 
#17 ·
Plain - the hum or growl noise you're talking about, did this happen only when the ambient temp dropped below or around 32degs then went away after driving for approx 2 mins? I've had this howling noise in my 2010 OB 2.5 since 20k miles (60k now). Every winter it comes back. The colder it is the worse & longer it lasts. I've had it at the dealer about 4 times. Even SOA regional rep checked it out and said it's normal CVT noise. BS. Not one other person on this board has reported this. I'm wondering if it's a wheel bearing... Think rubbing your finger around a crystal wine glass as the sound it makes. The faster you drive the higher the pitch. Happens between 1,500 and 2,000 RPM neutral or drive - but mostly drive...
 
#18 ·
No. The bearings on my 07 developed the hum/growl and it remained regardless of outside temperature, and didn't go away after driving for a while.

But I wouldn't say my symptoms are the only ones possible. Others have reported anything from grinding to heating and, at the extreme, looseness.
 
#21 ·
This thread is so timely for me...
My 2000 ob has been making wheel bearing noise ever since I bought it in '07 @ 82,000. Now at 145,000 it's suddenly gotten much worse. Two mechanics have said it's not dangerous (they felt very little play in the wheel) and the second one said it's "flat spots on the bearings".
The frame of this car is pretty rusted and I was debating whether to fix these or not. If they're not loose are they still potentially dangerous? The noise is loud enough to be unnerving when turning the wheel even the slightest amount and worse at higher speeds.
My own car knowledge is pretty marginal so I'm depending on the mechanic's opinion but I'm less and less confident about that...
 
#24 ·
If they're not loose are they still potentially dangerous? The noise is loud enough to be unnerving when turning the wheel even the slightest amount and worse at higher speeds.
i would consider them potentially dangerous. i've seen them exhibit no play on the vehicle and have significant issues when disassembled.

full disclosure - i've never seen a wheel bearing completely fail catastrophically and by forum threads it is seemingly rare. so i guess in some ways it's not that common to have a dangerous, catastrophic failure....it's probably very very unlikely. yet given the nature of a wheel bearing i'm not sure i want to tempt that either.

i would at most - just keep an eye on how much it's getting worse. they'll gradually get louder and louder and more play as damage increases - as soon as it starts to escalate fast - i'd park it. if you really wanted to limp it along a few more miles - squirt some additional grease in it - though i don't know that you can actually get any grease easily to the bearing. you could slide the axle out and get it around the bearings....

if you see the ABS light come on, i'd consider you're driving on very limited time...but by that point it should feel really scary and squirrely. the play causes the ABS tone ring/ABS sensor to get clipped and damaged triggering the ABS light. the ones i've drove like that though are notably squirmy steering and tracking though so you'd likely be timid well before then even.
 
#27 ·
2005 Outback @ 80,000ish miles making noise. Could tell front but not which side. Found a winding paved road safe @ 50 mph (but would be pushing it @ 65). Curving right still had noise. Curving left, unloading bearing somewhat, noise went away. Replaced left front bearing and noise gone.
 
#29 ·
This is very similar to what mine is doing but it makes noise when turning in either direction.

$300 is insanely cheap for two bearings!

i'd just replace one, there's no need or reason at all to replace a bearing without issues.

sounds like you're done with the car personally but more than likely the rust probably isn't catastrophic. it's annoying and sucks and maybe you should get out before it does progress to annoying levels but unfortunately common for the northeast.
I thought the price was cheap too and I'll have to confirm that it includes parts. Backyard mechanic who knows my daughter well. He'll need to take the bearings to a buddy with a press... if that gives you an idea of who he is. I *think* he knows what he's doing....

If it doesnt' seem loose, how to tell which bearing is bad? The car makes noise turning in either direction.

I'm really not done with th car at all if it will continue to go. I'd like to find a newer one and turn this into a kayaking/fishing/work vehicle. This backyard mechanic said he can put his fingers through some spots in the frame. Is there a way to determine just how bad it is?

Thanks for your thoughts
 
#30 ·
which side: sound and temperature

rust: Post a picture of it here.

otherwise it's tricky in general:
1. people outside the rust belt freak out about things that are "normal" here, so their diagnosis may be correct down there "wow this is terrible, the worst i've ever seen, this is scrap down here" and yet normal up here.

2. "hole through the frame" - depends what you mean. poking a hole in a fender corner or dogleg is no big deal. i have a 2003 with an enormous hole i could fit a potato through....but it's in the typical dogleg spot and not a big deal. i've got a replacement to cut and weld in only because i'm selling the car. otherwise the rust is rather minimal on that car underneath in the strucural/mechanical/important areas.

post a picture of said rust, but there's a good chance you have many more years and don't need to worry about it.
 
#31 ·
I was at the mechanic's when the car was jacked up with the wheels off. When pressing on the accelerator, the right front wheel seemed to "catch" or hang up quite a bit so that it would turn in fits and starts. Very uneven. Since I'm not a mechanic and am even more clueless about awd, this could be normal for all I know. The mechanic seemed to think it was due to flat spots in the bearings.

Pouring rain here today. I'll take a picture or two when I can. I like the car and in fact I like the older, less SUV-like Outbacks more than I do the new ones.
 
#32 ·
Hmmmm, I wouldn't take that wheel spin as indicative of a Subaru wheel bearing issue. If the wheel bearing is bad enough to cause that - you should be able to feel it by hand i would think.

Next time while the wheels are spinning - put a stethoscope on the knuckle.

That's probably the brakes, axle, front differential/AWD activity making it do that.
 
#33 ·
The end result...
I had both bearings replaced for $400 which was an especially good deal given that the mechanic had to deal with rusted bolts, one of which he had to redo with a helicoil repair. (I had to look it up) Also a note that the "driver side hub is fused to strut". I know he ate some time for things that didn't go right and I softened the blow a little with cash and a pound of freshly caught shrimp. The car sounds better than it ever has since I bought it in '07.

I tried to take pics of the undercarriage rust with my phone but they came out blurry. The mechanic's opinion was that it should go for a few years yet. Judging from his truck, he would know about driving a vehicle right to the last....

Thanks for the help here and Happy Thanksgiving to all!
 
#35 ·
The end result...
I had both bearings replaced for $400!
that's a good deal even if it's easy peasy.

Also a note that the "driver side hub is fused to strut".
Those two parts don't touch each other. If he's using the generic "hub" to mean the knuckle - those are always separable. no matter, you can ask/figure it out if need be.

I softened the blow a little with cash and a pound of freshly caught shrimp.
Hey, I may have come and done the job for some shrimp!

Judging from his truck, he would know about driving a vehicle right to the last....
HA HA!!
 
#38 ·
Agreed, been to Seabrooke and Kiawha Islands a few times and Edisto Island this year. Gladly offset gas for the next trip with some Subaru tinkering! lol

And if you don't need any work I'll just wave down the 2 Subarus I see and one should be you right? lol
 
#41 ·
Hey GrossGary,
are you up on used suby prices? I'm looking at a 2008 limited outback.... looks very well kept, has a few tiny paint chips on the hood that show rust but otherwise looks very nice. 78,000 miles and he's asking $11,900. That seems higher than edmunds, lower than KBB. I'd like newer just for some of the bells and whistles but thought I'd go for teh lower budget option...
 
#42 ·
KBB is always high, i generally ignore that. use edmunds and even online listings - autotrader as a guide. look for trends, not outliers for an average price as a start.

it's tax return season so if it's a dealer they're going to start high and keep it high. they know vast herds of people are planning on buying cars right now with their returns.
 
#43 ·
Looking at all the info I can find online, I think if I can get him down to $11,000 it'll be about as good as it gets. There is a place downtown Charleston called The Suby Doctors. I'll get them to look it over.

It's a LTD model with automatic and VDC. Is the VDC a useful feature for the average driver? I'd never heard of it.
 
#46 ·
Hello, My 2010 Outback needs new wheel bearings, DF and PR.
I hope this isn't a breach of any rules, but can someone suggest an online source? Any help and direction is really appreciated.
Try to stick to a good name brand hub assembly like SKF or F.A.G. They usually come with at least an 18 mo. warranty. The biggest mistake people make is over-torquing the axle nut with an impact gun. Just because you took it off with an impact gun, doesn't mean it has to be installed with one. Find the proper torque spec or you'll be changing it again...sooner than you think.
 
#45 ·
I'd get them from Subaru. Subaru online dealers are about 20% less than local dealers.

the newer bearings are bolt in with the ABS tone ring included and some aftermarket ones don't play nice and render the ABS non-functional. of course if you're game for a little risk and extra work - then just get an aftermarket one and return it if it's bad.

if the fronts are standard press in bearings like older models then those routinely take aftermarkets just fine. Though i'd still lean towards Beck Arnley or some name brand.
 
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