underside droning

[timetraveller]

hi all
im getting a noticable droning sound at around 40 mph that seems to be coming from either the gearbox,front passenger wheel or around this area and im not sure what it is
its hard to pin down where a noise is coming from i know but its best described as a drone
it does it when in gear and freewheeling ??
i thought it was the wheel bearing so i replaced that but its still the same
any ideas anyone ??
thanks
Neil

[bmcecosse]

Hmmm - is there (engine) oil in the gearbox and EP90 in the back axle? Prop shaft joints not loose - and recently greased? Is the exhaust clear of the body - not rubbing where it leaves the engine compartment??

[beero]

You could put the back axle on axle stands, chock the front wheels, start it, put it in gear and run it up to 40mph.
If the droning is still there it rules out the front wheels.
You may also see where the noise is coming from or what is vibrating.
Do be careful though.

[timetraveller]

Hmmm - is there (engine) oil in the gearbox and EP90 in the back axle? Prop shaft joints not loose - and recently greased? Is the exhaust clear of the body - not rubbing where it leaves the engine compartment??

yes gearbox oil full,exhaust clear of body

will look into back axle oil and propshaft joints

[timetraveller]

an update on this as its still occuring
i have tried 2 new hubs with new or different bearings which are ok for a few miles then the noise starts again
i have located the noise to the passenger front wheel
its recently had some new brake shoes fitted and thought these may be rubbing or touching the drum but the wheel rotates freely enough
how tight should the castellated nut holding the hub on be ???...as i dont want to overtighten it and put too much strain on the bearing preload
i really am at a loss with this now and its taking my life over worrying about it

[mike.perry]

There is no preload on roller bearings, the nut should be tight, 40lbs.ft, and lined up with the split pin hole in the stub axle.
Check that body panels eg gearbox cover are screwed down tight or anything loose in engine bay.
Check if gear lever vibrating
Check if propshaft out of balance or UJs need replacing

[Fingolfin]

Is there a noticeable vibration that you can feel when driving? If there is, note where you feel it -- through steering wheel? Toeboard? Pedals? Gearshift?
Have you checked that the rubber bits holding the exhaust clear of the body are still softish and not rock? Same for gearbox and engine mounts, and perhaps (though not likely with the symptoms you cite) the suspension bushings.
On that line of thought...is the suspension solidly in, i.e. all the nuts and bolts done up tight? No motion? Is the steering rack in tightly? Do any of the linkages have any play in them? Are all the suspension parts well lubricated? When you bounce the front of the car, is there any 'clonk' in the damper?
I'm just throwing out every idea that comes to me. No promises.

[kennatt]

well you have located the fault to the front passenger side and you say it goes away witha new bearing/hub and comes back after a few miles so it has to be the bearing, have you tried retightening to 40 to see if something is coming loose

[katy]

There is no preload on roller bearings

I thought there was ball bearings in the front wheel hubs? Was there a change-up somewhere along the way?

[robedney]

Sounds as if you've run over a piper. Nuisance, that. BMC may want to chime in here, but as I recall on the modern Scottish pipes there are two tenor drones and one bass drone. The bags are probably inflating in the air flow under the car. Just scrape off all the remains and you'll be good to go.

[bmcecosse]