Cyclical "Thumping" Coming From Rear of Car

[Daskuppler]

Hello Everyone,

 

I have a '14 Forester Premium with 112k on it.  I am on a road trip and about 800 miles into the trip, I started hearing a cyclical thumping coming from the back of the car.  The best I can tell is that it is coming from the rear passenger tire. The wheel bearing was replaced on that wheel approximately 10k ago, I do not feel anymore heat in the passenger hub versus the driver, but that's not exactly a scientific approach to feel it haha.  I still have about 3000 miles to go.  Thoughts?  I have some tools but limited so there's no replacing the hub or CV axle.  Could it be anything else?  Any way to isolate one from the other?  A bad CV might make it home, a bad hub could be catastrophic.

About the same time the noise developed, the car seems to have developed a little bit of stumble under about half load and between 2k and 3k rpms.  It's very pronounced, no CEL and it doesn't really feel like a misfire.  It's there every time and not present under full load.  Also, the SRS light has started coming on periodically.  I suspect this is just a bad connection, but you never know what systems are connected these days.

 

Thoughts?

 

Cheers,

Andrew

[brus brother]

lug nuts tight?

[Daskuppler]

41 minutes ago, brus brother said:

lug nuts tight?

Good point, I'll check them in the morning. We just got new tires right before the trip.

[brus brother]

new tires? if lug nuts tight try swapping tires back to front. see if noise travels with tire. possibly defective tire.

common things occur commonly.

[idosubaru]

Sorry you're on a road trip.  Brus offfered to help me on a 1,500 mile road trip 2 years ago and here he is again!

Did it randomly start happening or has it been getting progressively louder?  If it starts getting worse quickly then that's a bad sign.

I would guess it's the tire or the wheel bearing is aftermarket and noisy.  The good news is that it'll come apart very easily if it was just done recently.  I would replace with a Subaru unit.

I'm not recommending anything since I can't see or experience it or know it's history but I'll drive failing OEM bearings thousands of miles until I can combine replacement with brakes or tire rotation/swap.  In my experience if the noise isn't getting worse quickly and I don't have any *actual drivability symptoms* I'm not worried about OEM bearings. 

Symptoms - If the car has momentary walking (feels like a really brief slide on ice/snow in the rear) or loose steering feel, or the ABS light comes on (reduced clearances on the internal ABS parts will trigger the ABS light - those are signs the wheel bearing is actually failing verses just making noise.

I've seen and driven Subarus with all of those symptoms before. 

Check for noise/feel, temp, or play - but they don't always exhibit symptoms at all. 

Noise/feel you can try to do by just rotating the tire by hand but works best with tire and brake pads removed - rotate and listen for noise or feel for a lumpy/lagging/dragging part of the rotation.  Subaru's exhibit play so rarely, or the symptoms are so bad by the time they do exhibit play that this is the least effective test). 

Edited May 26, 2022 by idosubaru

[brus brother]

1 hour ago, idosubaru said:

Brus offfered to help me on a 1,500 mile road trip 2 years ago and here he is again!

Roadside assistance only available in New England ;-)

[forester2002s]

Could the thumping be from the rear driveshaft? U-joints or bearing?

If so, I would expect a difference in thumping when accelerating vs. coasting.

[idosubaru]

13 minutes ago, forester2002s said:

Could the thumping be from the rear driveshaft? U-joints or bearing?

If so, I would expect a difference in thumping when accelerating vs. coasting.

The comment "rear passengers side" suggests (but doesn't confirm) it's isolated to something side specific.  Driveshaft is usually notably center/not side specific. 

Riding/listening from the back while someone else drives can help confirm. 

[1 Lucky Texan]

all 4 new tires? all tires must be the same size/model/brand and near each other in wear. Will the car perform smooth, slow tight circles on dry pavement? no jerking/binding?

[brus brother]

My experience with drive shaft was when taking off from start and I would feel it in the center as ido suggests.

[Daskuppler]

1 hour ago, brus brother said:

Roadside assistance only available in New England ;-)

 

50 minutes ago, forester2002s said:

Could the thumping be from the rear driveshaft? U-joints or bearing?

If so, I would expect a difference in thumping when accelerating vs. coasting.

It's definitely present all of the time over about 20mph.  At higher speeds it is hard to hear due to road noise, but still present.

33 minutes ago, idosubaru said:

The comment "rear passengers side" suggests (but doesn't confirm) it's isolated to something side specific.  Driveshaft is usually notably center/not side specific. 

Riding/listening from the back while someone else drives can help confirm. 

We did just this, my wife drove and I put my head out the back window.  The noise was very specifically coming from the rear passenger side.  It sounded scratchier outside by the wheel than it does in the cab, but nonetheless it is coming from the rear passenger.

25 minutes ago, 1 Lucky Texan said:

all 4 new tires? all tires must be the same size/model/brand and near each other in wear. Will the car perform smooth, slow tight circles on dry pavement? no jerking/binding?

4 new Continental TrueContact tires.  I have not tried the tight circles, I thought that really only diagnosed the front end.  I'll give it a go in the next parking lot.

 

1 hour ago, brus brother said:

Roadside assistance only available in New England ;-)

I'm currently in Oregon.

2 hours ago, idosubaru said:

Sorry you're on a road trip.  Brus offfered to help me on a 1,500 mile road trip 2 years ago and here he is again!

Did it randomly start happening or has it been getting progressively louder?  If it starts getting worse quickly then that's a bad sign.

I would guess it's the tire or the wheel bearing is aftermarket and noisy.  The good news is that it'll come apart very easily if it was just done recently.  I would replace with a Subaru unit.

I'm not recommending anything since I can't see or experience it or know it's history but I'll drive failing OEM bearings thousands of miles until I can combine replacement with brakes or tire rotation/swap.  In my experience if the noise isn't getting worse quickly and I don't have any *actual drivability symptoms* I'm not worried about OEM bearings. 

Symptoms - If the car has momentary walking (feels like a really brief slide on ice/snow in the rear) or loose steering feel, or the ABS light comes on (reduced clearances on the internal ABS parts will trigger the ABS light - those are signs the wheel bearing is actually failing verses just making noise.

I've seen and driven Subarus with all of those symptoms before. 

Check for noise/feel, temp, or play - but they don't always exhibit symptoms at all. 

Noise/feel you can try to do by just rotating the tire by hand but works best with tire and brake pads removed - rotate and listen for noise or feel for a lumpy/lagging/dragging part of the rotation.  Subaru's exhibit play so rarely, or the symptoms are so bad by the time they do exhibit play that this is the least effective test). 

The wheel bearing is a Moog (yeah I know they have fallen a lot from where they used to be, it was roughly $200 and the only thing available locally and I needed the car back on the road).  I have no ABS light, just the random SRS light (I haven't bothered to hook up the code reader and see what's going. 

The car still tracks fine, there is no abnormal tire wear, no traction control activation or ABS activation.  Apart from the slight hesitation that presents kind of like a missfire, but feels much "smoother" the car drives fine.  No lack of power, it drives fine off road and in snow and ice.  The CVT fluid was changed before the trip with Subaru CVTF-II so it's fresh as well.  Apart from burning oil, it seems to be running great.

 

Lug buts are all tight.  I did not rotate tires as all I have is the scissor jack.  I could throw the spare on, but I feel like if a belt had slipped the tire should be noticeably deformed or show signs of irregular wear.  If I am wrong though, I can certainly try this out.

[brus brother]

yeah, use the spare as a placeholder as you swap tires L to R or forward aft.

 

[brus brother]

check wheel for balance

 

Edited May 27, 2022 by brus brother

[idosubaru]

Wheel bearing.

Other possibilities exist but wheel bearing would be “yep, no surprise with everything you’ve described so far.”  Anything else would be “ah okay that happens sometimes”.

It doesn’t change sound or feel when you press the brake pedal right? 

[Daskuppler]

Just got it back from a shop. The passenger bearing was about ready to come apart and the driver was almost seized.

[idosubaru]

1 hour ago, Daskuppler said:

Just got it back from a shop. The passenger bearing was about ready to come apart and the driver was almost seized.

Great thanks for posting back. Glad you you were able to get it taken care of. 

[Daskuppler]

22 minutes ago, idosubaru said:

Great thanks for posting back. Glad you you were able to get it taken care of. 

You're welcome. The stuttering has gone away as well so that should be a clue as to how bad the bearings were. They put Timkens in so they should be better.

[idosubaru]

44 minutes ago, Daskuppler said:

You're welcome. The stuttering has gone away as well so that should be a clue as to how bad the bearings were. They put Timkens in so they should be better.

Nice - two birds with one stone!  Well except you had to replace both bearings. 

Timken has an excellent reputation. I don’t think it’s what it once was and I believe their seal quality is less than OEM but chances are in your favor, it’s not like they fail all the time. 

[Daskuppler]

What are your thoughts on SKF bearings for the front?

[idosubaru]

On 5/30/2022 at 2:26 PM, Daskuppler said:

What are your thoughts on SKF bearings for the front?

Any aftermarket has a high chance of failure down the road. Including SKF.  I’m unsure but from the little I’m aware of aftermarket uses a worse seal than OEM. Maybe a single lip seal instead of double lip. And aftermarket as a whole is far worse at grease quality and quantity quality control. So there are known and highly suspect reasons aftermarket is lower grade in addition to those who are around a lot of Subaru just see more failures.

* If I saw a new Subaru bearing fail I’d be surprised and look into possible knuckle damage or prior accident history at that corner. I’ve never seen OEM replacement bearings fail and that’s what I predominately install. I have  no clue how many I’ve installed.

* If I saw any aftermarket brand fail Id consider it normal.  Ironically the last OEM bearing I installed two years ago on a 2006 Subaru is currently growling. I ordered front and rear for a Tribeca thinking I might get OEM from aftermarket (see catalog filling comments) since that’s a low volume vehicle. The front was.  The rear wasn’t and  its now noisy. Funny considering how much I avoid aftermarket  

Sometimes you can get lucky and actually get an OEM Japanese wheel bearing like NSK in the box of a beck Arnley or Timken.  but that’s rare and just when they want to fill out their product line and have to use the OEM supplier just to complete there Subaru offerings.  But I don’t think you’ll see that for a 2014 Forester. I think it happens for lower volume parts or rarely due to temporary volume logistics.

A. If you’re trying to fix it cheap and sell it 6 months use whatever you want. 

B. If you don’t mind an atrocious failure rate…like 30% down the road (imagine throwing up 3 out of 10 times at a restaurant - that’s how I view this). But - in defense of aftermarket wheel bearing lovers - this means you have a 70% chance of being fine. (I’m making up the numbers - but they’re significant, whatever they are, maybe worse.  I’m not a shop or mechanic and I see it though j don’t see enough volume to keep meaningful track of brands.  If you’re okay with that Use any decent brand aftermarket you’re comfortable with. 

This is also why you see tons of anecdotal evidence on line “I installed this bearing and it’s fine”. Of course you did. no one is saying they never work, but the failure rate is bad. That’s like saying you never lock your car in big cities and haven’t ever had an issue. Good for you but that’s short sighted. And many people don’t keep a car long enough or are around a lot of Subarus long term to see these high rates of issues.

C. Unfortunately Subaru is the only near 100% success rate option.  If you’re paying for labor no way would I buy aftermarket. Too much effort and risk getting stranded with another shop, or happening after your warranty and paying again. If you’re DIY it’s almost not worth it because any job is so cheap youre time is worth more than the parts price difference on this job. I’m not an all OEM guy but for wheel bearings I am.

Edited May 31, 2022 by idosubaru

[Daskuppler]

23 minutes ago, idosubaru said:

Any aftermarket has a high chance of failure down the road. Including SKF.  I’m unsure but from the little I’m aware of aftermarket uses a worse seal than OEM. Maybe a single lip seal instead of double lip. And aftermarket as a whole is far worse at grease quality and quantity quality control. So there are known and highly suspect reasons aftermarket is lower grade in addition to those who are around a lot of Subaru just see more failures.

* If I saw a new Subaru bearing fail I’d be surprised and look into possible knuckle damage or prior accident history at that corner. I’ve never seen OEM replacement bearings fail and that’s what I predominately install. I have  no clue how many I’ve installed.

* If I saw any aftermarket brand fail Id consider it normal.  Ironically the last OEM bearing I installed two years ago on a 2006 Subaru is currently growling. I ordered front and rear for a Tribeca thinking I might get OEM from aftermarket (see catalog filling comments) since that’s a low volume vehicle. The front was.  The rear wasn’t and  its now noisy. Funny considering how much I avoid aftermarket  

Sometimes you can get lucky and actually get an OEM Japanese wheel bearing like NSK in the box of a beck Arnley or Timken.  but that’s rare and just when they want to fill out their product line and have to use the OEM supplier just to complete there Subaru offerings.  But I don’t think you’ll see that for a 2014 Forester. I think it happens for lower volume parts or rarely due to temporary volume logistics.

A. If you’re trying to fix it cheap and sell it 6 months use whatever you want. 

B. If you don’t mind an atrocious failure rate…like 30% down the road (imagine throwing up 3 out of 10 times at a restaurant - that’s how I view this). But - in defense of aftermarket wheel bearing lovers - this means you have a 70% chance of being fine. (I’m making up the numbers - but they’re significant, whatever they are, maybe worse.  I’m not a shop or mechanic and I see it though j don’t see enough volume to keep meaningful track of brands.  If you’re okay with that Use any decent brand aftermarket you’re comfortable with. 

This is also why you see tons of anecdotal evidence on line “I installed this bearing and it’s fine”. Of course you did. no one is saying they never work, but the failure rate is bad. That’s like saying you never lock your car in big cities and haven’t ever had an issue. Good for you but that’s short sighted. And many people don’t keep a car long enough or are around a lot of Subarus long term to see these high rates of issues.

C. Unfortunately Subaru is the only near 100% success rate option.  If you’re paying for labor no way would I buy aftermarket. Too much effort and risk getting stranded with another shop, or happening after your warranty and paying again. If you’re DIY it’s almost not worth it because any job is so cheap youre time is worth more than the parts price difference on this job. I’m not an all OEM guy but for wheel bearings I am.

Thanks for your input.  I actually decided earlier today to go wit the OEM bearings so I will be picking up two of them tomorrow.  Unfortunately, the shop that replaced the rears told me they were using OEM but installed Timkens.  I usually do everything but internal engine and transmission work myself, but all I had was a small tool box, a bummed back and raining weather at an Airbnb so the shop did the rears.

Thank you for your input!  I used to be a big fan of aftermarket stuff, but I find as time goes on the quality keeps going down.

[idosubaru]

I get it. I wouldn’t fault someone for using aftermarket. Batting .700 is phenomenal in baseball and some people might be fine with that. It’s still good to know particularly so one doesn’t overlook them as potential sources of issues just because they’re new.

It’s good to ask - some parts like radiators are excellent aftermarket options.

Aftermarket wheel bearings also fail much faster than OEM and my time is too valuable to redo a job like this stupid Tribeca bearing I thought I’d be cute and try aftermarkets on.  At least it’ll come out easy being newly installed.