XC70: Bearing noise when cresting hills

[Rich1e2001]

Getting a distinctly bearing sounding rumble / hum from the front of the car when the car is unweighted (or less weighted) i.e. when cresting the brow of a hill. Feels like it's coming from the drive shaft(s) but thats just a guess. It doesn't appear any other time and diminishes as the car warms up. Any one have any idea what this might be?

[Clan]

Originally Posted by Rich1e2001

Getting a distinctly bearing sounding rumble / hum from the front of the car when the car is unweighted (or less weighted) i.e. when cresting the brow of a hill. Feels like it's coming from the drive shaft(s) but thats just a guess. It doesn't appear any other time and diminishes as the car warms up. Any one have any idea what this might be?

tyres have been making noises like that for the last 8 years or so.. have you rotated them looking for uneven shapes in the rubber?

[Tannaton]

^^^ That - I'd swap fronts & rears and see if it makes any difference?

[Rich1e2001]

Due to a dangerous combination of having very little time and enthusiasm to swap the wheels around I've not yet managed to do this yet (!) however I noticed that the noise doesn't appear under the same circumstances when not on the throttle i.e. coasting over the brow of a hill, only when on the throttle. For this reason I'm strongly suspecting it's not the tyres as surely this would be independent of throttle state?

[Rich1e2001]

Ok so now I have the knocking / clunking on full lock (low speed !) so pretty sure the rumble relates to a worn CV joint on drivers side. Dare I replace it myself - Volvo quoting ~£900 inc. VAT to save me the hassle...

[Puffster]

I used to get this - like a wittering sound when on the accelerator but nothing when off of it. It could be CV related, I've had a couple on the front driver side now but pretty sure it was still there after I had one replaced. I don't notice it now, will have a listen out.

[Puffster]

Originally Posted by Rich1e2001

Ok so now I have the knocking / clunking on full lock (low speed !) so pretty sure the rumble relates to a worn CV joint on drivers side. Dare I replace it myself - Volvo quoting ~£900 inc. VAT to save me the hassle...

That's a lot of money for a reasonably straightforward job. An Indi will do that so much cheaper both in terms of labour and parts. Don't worry about not getting Volvo part as even if you have to replace in a couple of years, will still be cheaper that what they would have charged for the same (unbranded) part!

[Rich1e2001]

So, I ended up with a a failed drivers side wheel bearing which I replaced myself this weekend. This seems to have fixed the noise on cresting hills. I had a good check of the drive shaft on that side while I had it disconnected from the hub and couldn't find anything obviously wrong. If this was just a bearing problem I'm surprised it ran so long before it became the recognisable hum. It's also gone through a number of MOTs like this. On a side note, getting the gen 2 bearing out is not much fun and cannot recommend the eBay puller set - a hydraulic press is the way to do this. My kit is now thoroughly broken after one use and only just finished the job.
Trouble is you need that supporting plate to shove it on via the outer race only. Haven't seen a way to just buy a decent quality plate for the press.

[Tannaton]

Originally Posted by Rich1e2001

So, I ended up with a a failed drivers side wheel bearing which I replaced myself this weekend. This seems to have fixed the noise on cresting hills. I had a good check of the drive shaft on that side while I had it disconnected from the hub and couldn't find anything obviously wrong. If this was just a bearing problem I'm surprised it ran so long before it became the recognisable hum. It's also gone through a number of MOTs like this. On a side note, getting the gen 2 bearing out is not much fun and cannot recommend the eBay puller set - a hydraulic press is the way to do this. My kit is now thoroughly broken after one use and only just finished the job.
Trouble is you need that supporting plate to shove it on via the outer race only. Haven't seen a way to just buy a decent quality plate for the press.

Glad you got it sorted. Seen a few strange bearing issues on P3's over the years, including random ABS lights and issues that go away when replacing the bearing but no noticeable play or noise.

As you say, the cheap kits on ebay are disposable and sometimes dont work as all, the good kits are a good bit more more expensive than a second hand hydraulic press..... which has many other uses.