XC70 knocking at rear when cornering

[RogerTo]

Hi folks
Looking for similar experiences.
2008 XC70 with 4c. We have a subdued knocking at the rear passenger side when going round RH corners, ie when there’s extra load on that wheel. Not noticeable on the straight or on LH corners.

I’m pretty sick about it as we’ve just spent on timing belt, all discs and pads, and rear 4c shocks, rear shock top mounts, plus a couple of other bits in the last three weeks, and that’s a pretty penny.

We use Voltech in Glasgow and can’t fault them, I’ll give them a ring tomorrow, but the shocks were only done on Friday!

Any similar or any ideas?

[RogerTo]

Bit of a rubbing noise at the same time on occasion...

[john493]

Rear trailing arm bushes would be one of the first things to check.

[V8XCV]

And check the Anti roll bar drop link ball joints, they don't last that long.

The other thing it could be is a worn wheel bearing combined with a slightly warped or corroded brake disc (or sticky caliper piston) - when you corner the bearing allows some slight movement of the disc in relation to the brake pads and the disc will rub. If the disc is slightly warped or corroded then it will rub intermittently giving a thumping noise.

I would check disc condition and also check the wheel bearing for play, you could also try braking on a RH corner and see if it changes the noise.

[RogerTo]

Thanks for the suggestions. I had wondered about bushes but hadn’t had the squeaking that is commonly mentioned. I don’t know if they were done before I bought it (in 2015 at 90k miles) but we’ve done 85k since then...

I’d also wondered about wheel bearing, which might also explain the occasional rubbing, although they are new discs (3weeks ago) and I’d expect a bearing to be picked up then?

Probably get it back to Voltech on Friday, I’ll update.

[ferg55]

Is the knocking in time with the rotation of the wheels? That would narrow it down to discs / bearings.

If not, it's something loose - always worth checking some easy things before it goes to the garage like loose items in the boot or spare wheel well (e.g. the locking wheel nut key used recently), or if the exhaust has worked loose by giving it a waggle.

[RogerTo]

It seems associated with suspension movement, and I’ve checked the boot and exhaust as well, good shout.

[RogerTo]

Taking it in first thing tomorrow.

[RogerTo]

They couldn’t find anything...

Problem only appears after 5 miles or so, and took even longer this morning as I was driving to work after having it looked at, a good 20 miles (of motorway - no challenging RH corners in that time.

So my theory is a wheel bearing that goes out of tolerance once it warms up. Maybe at the weekend I’ll drive about and get it hot and knocking then quickly lift it and see if any play. The garage this morning left a good 30 mins before looking at it, and only took it out on road for 5 mins or so.

Thoughts??