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Hi All,
I have a 91 FWD Liberty. I've noticed a grumbly whine that seems to be coming from the passenger side rear. Several times in the past couple of weeks, I've jacked it up and spun the wheel by hand. There's no play, no grumble, no roughness that would indicate a crook wheel bearing. Nor on any of the other wheels for that matter. After a drive no hub is significantly hotter than any of the others. So apart from the sound, I'm tending to eliminate a wheel bearing as the culprit.
So, are there any people out there with any other ideas?

Try gently swaying the car from side to side without crossing over the middle of the road when it is at its loudest and it might tell you which side to investigate further. If the noise gets louder when the weight of the car is greater, and quieter when the weight of the car is off that side, it will be that side that the noise is coming from. I mean swerve right and the weight will shift to the left side and vice versa.

Thanks Busdriver, been there, done that, no significant change in sound level. What baffles us is that whilst the sound is there, there are no other signs of a damaged wheel bearing. Is there any chance it is something else? Tyre noise maybe? But then, why on one side and not the other? (Same tyres all round btw)
Definitely need help, hubby's grumbling and whining is getting noisier than the cars!

What speed is the noise the loudest at? Does it just get louder the faster you go or does it disappear at some point? Tyre delamination perhaps? Check for any raised tread areas? Diff noise maybe also,does it change when you go from throttle on to throttle off? Check that the rear diff is full of oil. Maybe remove the tail shaft and take it for a spin and see if that removes the noise at all. While its out could be a good time to check the uni joints and centre bearing.

Check the tread on the tyres, sometimes when they chew the edges and make them uneven it can sound like a wheel bearing..

@ Busdriver - Can't hear it at low speed, sound builds up from about 20-30kms and just gets louder from there. As to the rest, it's a two wheel drive, not AWD so can't disconnect the tail shaft lol. All fluids are at the correct levels.

@ Wagonman - The tyres are slightly oversize, 215/45/17. I think off an Outback? or Forrester maybe? And sides are slightly scuffed from rubbing on the wheel arches occasionally. However the main tread area is fine.

Sorry, took you saying it was FWD to mean Four Wheel Drive,not Front Wheel Drive. If its not Tyre or wheel bearing it doesn't really leave a lot then now.

Swap tyres around the vehicle and see if the noise moves with it.

It's pretty common for the rear left bearing to go first. It could be worth pulling it down to check it out, if it checks out all good you can add some fresh grease while you're there to help with looking after the bearings.

Cheers

Bennie

Update:
Today we pulled off the wheels, disc calipers and discs and spun the hubs back and forth. We detected no roughness in the rotation, and could hear no noise at all indicating a crook wheel bearing when we listened with a stethoscope.
Reassembled the car, took it for a run and the noise is still there. We can only assume at thhis point that it is tyre noise on the road. At least until any other symptoms appear indicating it is definitely a wheel bearing. But we'll keep a close eye on it all the same.
Thanks for the advice fellas.

does the strut move up and down smoothly?

Struts on the rear were rebuilt less than 18 months ago. No probs there.

Check for feathering of the tyres caused by poor wheel alignment. This is commonly mistaken for a dying front gearbox or wheel bearing.

Spinning the wheels by hand will not prove a wheel bearing is ok.

Could also be a bent/buckled wheel, tyre delamination, rear diff bearing, rear half shaft cv joint.