DB9 droning

[pancholi]

over the past 4 weeks the car has developed a deep droning sound around +/- 40mph
the sound is the same irrespective of the gear the car is in.
road surface makes no difference,
its harmonic in nature with a frequency of 2 seconds ( ie the drone rises and falls in volume every 2ish seconds)
i believe its coming from the rear of the car but i could be wrong.

gearbox oil, diff oil all upto date
gears engage and shift smoothly.

any ideas ?
cheers

[james-witton]

Is the wife in the car with you?

[pancholi]

should have excluded that in my diagnosis

[designforlife]

Rear wheel bearing?

[DB531]

designforlife said:

Rear wheel bearing?

+1

[Westlondondriver]

I took my Dad (80 years old) on a car rally in my DB11 and he said I should have my diff looked at since he could hear a pronounced whine from the rear under hard acceleration. I had to point out if wasn’t the diff but the sound of the wankel rotary engine in the RX7 behind trying to keep up !

[Johnny42]

Can you swap over the rear wheels easily? It could be abnormal tyre wear.

[Manx V8V]

Johnny42 said:

Can you swap over the rear wheels easily? It could be abnormal tyre wear.

The tyres will be directional so you would need to turn the actual tyres on the rims if swapping sides, not a problem for a tyre company to do for a small fee though.

[MarkM3Evoplus]

Check the tyres.

Had a set which wore unevenly (different heights of tread block) and created a droning sound like a wheel bearing.

[pancholi]

thanks for the ideas.
tyre tread is even
tyres were fitted about 2 years ago.

i looked into the issues re. wheel bearing.
i did the 40mph turn the steering wheel test and yes the drone diminishes when turning to the left.
so i think we may have the issue diagnosed

i presume the DB9 hub is not shared from Fords parts bin eg....mondeo/transit/focus....
as the aston hub is £300+fitting

thanks again

[Veg]

It is a generic wheel bearing assembly which should be a straight bolt in affair. Around £250 for an Aston item cheaper if you shop around. I think a Ford F150 is the same but could be very wrong. A dealer is going to be £450-600 all in.

It costs a lot more at a garage to fit as the upright is aluminium and the bearing is hardened steel so they undergo a bit/loads of galvanic corrosion so stick together as if welded. To deal with this it entails taking the upright out so get a proper set of ball joint splitters not the usual crud from Halfords.

Once out my V8V took 20 tonnes of pressure over 2 days to get the bearing out of the upright. I also tickled the joint with light heat as heavy heat can melt / distort the aluminium - hell of a tense moment. Once out clean the surfaces and, I was given a top tip, coat the contact surfaces with a light coat of lacquer. Then liberal amounts of aluminium grease.

[pancholi]

thanks for the guidance on removal.
I usually DIY most jobs.
But this could potentially be a herculean task.
I am going to let the garage sorry this out.
I have been warned.. Thanks again

[Veg]

My conclusion too in hindsight. Any garage can do it doesn't need to be Aston. Just let them have the workshop manual pages!