Four months ago I noticed a faint rhythmic sound coming from the nearside rear. Almost like something caught in the tread of the tyre. The sound speeds up and slows down proportionally to the speed of the car, even with the gearbox in neutral and engine idle, and most prominent around 30mph. The sound has got progressively louder in the last few weeks. I've just replaced the rear discs, pads and tyres ahead of its MOT, but the sound is still present. It doesn't change under braking, or gentle weaving. There is no vibration. Could this be driveshaft wear?

 

Greetings....
More than likely that you have a failing wheel bearing, common on the rear of these cars due to the rear discs overheating (they are single piece items i.e not vented) ,therefore it places more stress on the wheel bearings.
With the car raised fully at the back using the differential donut as your support mount, do the usual check holding wheel at 3 o'clock and 9 o'clock and attempt to shake wheel. Also release handbrake and spin the wheel. You still may not noticed much difference however in play, or grinding noise.
Parts are relatively cheap, you are likely though to need the hub too as usually the wheel bearing race wears/scores into the hub, meaning you'll need both items. A good garage will determine it for you if you aren't sure, before you spend money replacing.
If you replace just the wheel bearing without replacing the hub, it won't take long for the new bearing to fail. You'll also need a new hub nut (should be supplied with the hub), and it needs torque beyond factory spec, to around 250lbft.
Good luck
I can get you part numbers if you need help

 

Thanks for the reply. It's been up on the ramp and there's no obvious play in the wheel at all, and the wheel seems to turn without any sound. I'm happy to replace the wheel bearing and hub to eliminate those before looking at a driveshaft / CV issue. If you have the parts numbers to hand then I'd appreciate it. It's a 2004 model.

 

My wheel bearing issue was like rubbing a finger round a wine glass

I don't think driveshafts do that, you tend to get a vibration/grind

It has to be pressed out. I didn't need a hub.

 

Thanks for the reply. My noise is more a rhythmic whup whup whup, and about the tempo of a single wheel revolution I'd guess (rather than a fast repetitive sound coming from a faster moving driveshaft?). There's no constant whine or grinding sound, and no vibration. Under 25mph you can't hear anything. It needs that speed for the tempo to build up to something audible, but it's definitely getting louder as the weeks go by.