Intermittent rumbling & slight vibration from rear at speed
 

At 70+ motorway speeds, I am getting on frequent occasions a rumbling and vibration from the rear of the car that can build for a couple of miles or so, and then can fade away never to be felt or heard again on the journey. Any ideas? Diff? Wheel bearings? I'm on modest spacers at the back if you think that has anything to do with it, but I'm not convinced. Are there any other wear items back there. Mentioned it at my last service, but they couldn't replicat it.

Thanks,
Zip

I'd go with either wheel bearings or the infamous sticking rear handbrake cable / release which if you dont use the car much is a possiblity

Bearings would be a common one for that.

I'd be tempted to jack each of the rear wheels up in and turn and check it for rotation / play etc.

I had a similar issue a while ago. Intermittent vibration/rumble. Never quite worked out the pattern to it but usually started after a bit of enthusiastic acceleration on the motorway. Seemed to go away after 10 mins or so of gentler driving.

If I remember correctly, I had the wheels rebalanced and a proper (4-wheel) alignment done. Seemed to cure it.

Had similar symptoms last year and it was a sticking calliper+++

I was racking my brains what the cure was in my case. I was struggling to remember because I had a few different jobs done on the car at the time, full wheel alignment being one of them. But you're right, I also had a sticking rear caliper changed at the time. I remember now, that was it!

Hmmm...maybe my calipers are playing up. But the pattern is the same....up to speed on motorway, a few miles of rumble, then fading away. Can get pretty intrusive. I'll check wheel play again.

If you recall what any other solution was, please let me know.

Thanks,
Zip

What make of tyres are on it ?
Does sound like sticking calipers but have heard weird noises off tyres that can come and go , maybe worth swapping wheels around to see if noise transfers

And as another suggestion, what are your tread depths all round?

Tyres all good....MPSSs all round