Defender rumbles

I have a persistent rumble on my 2015 110; only 30k miles covered. There's a rumble which can become quite grindy-metallic at high speeds. It's got a low woop-woop-woop sound in time with wheel rotations. I assumed it was the wheel bearings because I run spacers. No big deal, so set to work. I only had time to do the fronts before I needed to use it again and was anticipating at least some reduction in the noise. But it's still there. I took the time to replace the swivel one shot in both sides. The old bearings looked as new. So, do I bother to do the rears in the hope it's them - I don't think it is. Surely nothing major has happened in only 30k miles, maybe. I read about prop UJ's which seems unlikely. There is a loud clonk when going to hard right steering lock that I haven't looked into yet - is it connected? Is the worst case that it's bearings elsewhere? Any ideas please.

Try removing front prop then go for a drive (centre diff locked).
Then try the same with the rear removed (obviously refit the fron one).

That should show if the props are causing the noise.

Might be the handbrake drum rumbling. I think (but not certain) that if you remove the rear prop you need to apply the handbrake to maintain drive. If the noise stops when you do this it will narrow the issue down to the prop or the drum.

Wimblowdriver said:

Might be the handbrake drum rumbling. I think (but not certain) that if you remove the rear prop you need to apply the handbrake to maintain drive. If the noise stops when you do this it will narrow the issue down to the prop or the drum.

Click to expand...

No, the handbrake doesn’t need applying, just use difflock. If you do use the handbrake, the drive will end up going through the centre diff, to the front prop.

It might be worth dismantling the hubs a little further next time you have the spanners out. A noise on full lock might implicate a CV joint.
I have something similar on mine. There's a kind of scrapy noise just audible over the sound of the engine, which can be heard at 30-50 mph. There's no accompanying vibration as you get when a prop is in the way out, the bearings are fine - smooth, no play and there's grease in them. Quiet on full lock, so no obvious problems with the CVs (but I haven't had them out yet to have a look). I thought I was getting a bit of brake pad rattle , but I think I can hear it with the brakes on. The brakes are fine - plenty of meat left on the pads, smooth progressive application and no sign of the discs running eccentrically.

For the moment it's not too bad, but I would like to sort it out sooner or later.

You do not always get vibration with a uj failure. I had one go recently which was causing an irritating chirping noice. I though it was brakes rattling at first but on inspection you could see the tell tale rust lines and beginnings of play in the uj (despite regular greasing), swapped it over and the noise disappeared. I would try as suggested above removing each prop in turn and going for a drive with diff lock engaged. If the noise is still present both times, you know it is not prop-shaft related.
A loud clunk on steering sounds less cv joint and more suspension related to me. Does it happen every time? It may be worth getting underneath with a bar and checking all of your front suspension bushes and making sure the spring is seated correctly.