Our 2014 focus has started making a slight humming noise near the front passenger side wheel at about 40mph. Is it likely to be anything but a wheel bearing?

Sod's law... We're going on holiday on Friday and have no other car. Is it save to use (we'll be doing about 800 miles driving in France). 

Could be worn pads/discs

55 minutes ago, DaveT70 said:

Could be worn pads/discs

Would that make a sound even when not braking?

Can do

2 minutes ago, DaveT70 said:

Can do

Ok, thank you.

I've looked at hiring a car for 2 weeks (£2k!), so I think we will just have to take our chances. No garages/mechanics free this week, and the noise is very feint. If it gets worse we'll make use of our overseas breakdown cover.

If you jack the car up and turn the wheel you'll be able to hear if it's the pads/discs.

If it is change them, it's really easy to do yourself, plenty of youtube videos, you will just need to get a 7mm Allen key, if you haven't got one.

If it's not the discs/pads worn then it can only be a wheel bearing or CV joint

Cheers, will take a look.

13 hours ago, hiace_drifter said:

Our 2014 focus has started making a slight humming noise near the front passenger side wheel at about 40mph. Is it likely to be anything but a wheel bearing?

 

I always drive around with the radio on.

One day I didn't use the radio and could hear a faint hum at road speed which sounded just like a wheel bearing on the way out.

Jacked it up as above and all wheels were tight and correct.

I even listened to each bearing with my stethoscope and all sounded normal.

Sod it, i'll keep driving till it becomes obvious where the bearing problem is.

Several months later it was still there and I convinced myself that it was slightly worse. I just carried on.

Then it disappeared, no background road speed hum at all.

It was from a tyre, I had 2 new tyres on the front and that fixed the noise.

Worth a thought,

ScaniaPBman.

 

It's best to spin the wheels with the caliper off or you do hear a slight grind from the brake area and if it is a bearing you can also feel the vibration in the strut above when spinning. You will know when it's a bearing as when moving in the direction of the bad one the noise gets louder you can test it by moving slowly side to side but unfortunately you can't test it on roundabouts if it's the passenger side. When mines was on the driver's side you could clearly hear it loader going around roundabouts. They start off with a small sound then eventually it starts to sound like there is something wrong with your gearbox and gets louder as the sound travels towards that way.

agreed on the tyres. I've had them hum quite a bit. you have any winter tyres you can swap to test it? 

On the bearing; i've had the front one gone on the Focus...the sound went from a hum to a low pitch drone, the i've had that side changed. The other side is still fine, and that was 5 years ago and some 50k miles ago. 

i've driven with the hum for about 2 months...a couple of thousand km, then it started bothering me enough to had it changed - but YMMW.

Once upon a time i caught a ride with a fellow...the bearing was literally louder than the engine - on the highway that was. I think he said it's been sounding like that for like 8 months...he's been wanting to sell the car and was very hesitant to invest anything into the car anymore.. well, i told him nicely, for the sake of his safety and that of his passangers, and anyone anywhere around him in traffic (thinking by myself FFS explicit words %#$& people like this actually exist, driving cars that sound like an $% airplane from WW2), to please get that bearing changed ASA(f)P .. so the car will be safe until he manages to sell it, which could take some time, considering the age etc. of the vehicle.

geez.

 

but again, YMMW.

 

Minor update ... garage took a look for us, and said bearings ok, it seemed to be worn rear tyres causing the noise. We had new tyres fitted on day before hols, then drove with a roofbox on (which changes the exterior noise!). It seems to have been sorted, but we will monitor.

 

We're still getting some noise, which seems to increase with speed. One garage said wheel bearings need doing, one said they don't. Grrr. Can you have a "safe" amount of noise as wheel bearings ages, or does noise mean replace straight away?

there is no safe amount that you could learn to tolerate till you get rid of the car..  because it will progressively get worse. 

noise means replace sooner rather than later. loud noise means replace straight away..

8 hours ago, monkey×wrench said:

noise means replace sooner rather than later. loud noise means replace straight away..

I better look to trade the missus in then !! 🤣

11 hours ago, monkey×wrench said:

there is no safe amount that you could learn to tolerate till you get rid of the car..  because it will progressively get worse. 

noise means replace sooner rather than later. loud noise means replace straight away..

Cheers, it is very subtle. I found a few examples on youtube of the sound and they are much louder/more "growly". I just worry we'll pay to replace the wheel bearings the noise is still there,

Looking at the last service record (March), they did not mention wheel bearings (I must have dreamt it!). There were a couple of advisory items:

1. rear axle bushes

2. offside front inner tie rod

If those items have worsened, would either of those cause a humming sound at 40mph? (worsening at higher speeds)

The sound seems to come from the front, but it's very hard to pin it down.

Tracking has been done, tyres fine.

Neither of those things will create a hum.  Inner tie rod 'might' cause a knock eventually but won't generally make any noise.  Rear axle bushes creak.

Diff bearings are a possibility.

Could swap wheels front to rear to rule out tyre noise.  You can't always 'see' a noisy tyre.

7 hours ago, TomsFocus said:

Neither of those things will create a hum.  Inner tie rod 'might' cause a knock eventually but won't generally make any noise.  Rear axle bushes creak.

Diff bearings are a possibility.

Could swap wheels front to rear to rule out tyre noise.  You can't always 'see' a noisy tyre.

Thanks - would worn diff bearings be easy to spot for a competent mechanic?

37 minutes ago, hiace_drifter said:

Thanks - would worn diff bearings be easy to spot for a competent mechanic?

Very difficult to diagnose at the early stages unfortunately.

There's usually a change in the sound between accelerating and over-run if it is the diff.

I'm waiting to hear from my garage ... they wondered whether the gearbox had run dry of oil*. Would that not give a warning light? 

*The reason they ask is that front driveshaft oil seals needed replacing at last service, and were done about 8 weeks later.

There's no oil level sensor for the gearbox, so no warning could be triggered.

Here's how I diagnosed a failing diff bearing on my Focus some years ago.

 

From what you say it does sound like a wheel bearing, but
which one? Here’s how I tracked down my suspicious whine.

First I just drove it around for a while, there was a faint
whine from the front left so I went straight in and changing the left wheel
bearing. Wrong. It made no difference.

Stung by this failure I stepped back a little and did the diagnostics properly.

To start with I purchased a mechanics stethoscope for a fiver. Then I put the front of the car up on two axle stands and chocked the rear wheels with the handbrake tight as well. Then I started the engine put
it in gear and set it running at 30MPH. The wheels are off the ground but
turning at a reasonable speed so the bearings are running round.

Next from underneath I put the stethoscope on the hub
carrier as close to the bearing as possible and listened. Then the other side, and
the drive shaft support bearing (my prime candidate for the cause of the
whine). All were humming away smoothly. If there was to be a bearing failure it
would have made distinctive noise clearly noticeable with the stethoscope.

I would suggest you do the same type of test on the rear
wheels getting a friend to spin the wheel for you while you are underneath
listening carefully.

WARNING. Going under a car which is up on stands with the wheels turning for an investigation
like this is a hazardous thing to do with all those moving unguarded parts. I
did it very slowly and carefully with someone in the driving seat at the
controls. All I can say is if you are not confident don’t do it. I told you it
was dangerous!

Well where was my whine coming from? It didn’t take me long
to pin it down from under the front.

It was the left side final drive gear support bearing way
inside the gearbox. Bad news.

If you are getting your whine on corners, this technique
should help you identify the cause with confidence. A failing bearing will be
picked up like this with no cornering load or vehicle road load.

ScaniaPBman.

 

I have had a lot of satisfaction from my stethoscope. Once you get used to a 'good' bearing noise, then a failing bearing will stand out like a sore thumb. Just keep probing around underneath and you will find the source of your noise.

 

ScaniaPBman