I get the back of the car up in the air today to investigate the grumbling rear bearing.

‘Driving’ the car while in the air, the grumbling noise is clear to hear if I knock it into neutral at about 50mph. I suspect this is the rear right wheel bearing, so decide to take that out of the equation:

I repeat the ‘drive’ process, and there’s no noise. So if it isn’t the rear right wheel bearing, it’s something very particular inside the differential. I’m certain now that it’s worth changing the wheel bearing.

Finally, a big thanks to Olly Bloxham for sourcing the BMW service spark plug change tool for me shown below.

For anyone who needs one, it’s part number 80.00.0.121.160 and should cost about £20. [Note – it’s just the socket on the end of the 3/8″ extension bar]