Brakes: Front end clonk when stopping

[SwissXC90]

Today I heard an alarming metallic clonk from my front left wheel when the vehicle came to a full stop

VEHICLE
Car is a MY09 XC90 LHD with 115000km (72000 miles), always serviced religiously once a year at the same main Volvo dealer since new.

HISTORY
New front discs and pads were fitted in December 2016 by the main Volvo dealer during the annual service, no issues with braking or unusual noise until today
New rear pads were fitted in October 2015.

At the same Dec 2016 service the mechanic also greased my front hub splines to stop axle ping, that has gone away, no more ping present when shifting R-N-D-N-R. Checked again today, axle is silent.

Summer wheels were fitted last weekend by me.
This was the first 30min drive after fitting, but I have had some short drives around town where I noticed nothing.
I drove the car today up to 120kmph, with no abnormalities noted: no vibration from the front end (I especially took notice of vibrations to check if my wheel balancing is still ok), nothing to indicate a loose wheel.
Wheel nuts were tighter with an electric impact driver set to stop at the correct torque.

SYMPTOMS
The brakes feel normal, stop the car same as ever, no squeaks or grinding noises or vibration either low or high speed braking.

If braking to a stop from a slow coast, no noise

BUT when braking to a stop from say above 10kmph, there is a clonk when the vehicle comes to a rest, from front left only, and *appears* to coincide to the transmission releasing the pressure on the front axle.

There is no noise if the car does not stop, e.g. braking to slow down but not coming to a full stop.

It is a metallic sound, not a dull thud. And quite loud when the front left window is open.



So I am puzzled as to the clunk noise.

I am wondering if this is
1. CV joint wear?
2. Brake pads shifting in their housing?
3. Suspension bushing wear?
4. Worn control arm bushings?
5. Motor mounts failed?

PS: the sound is very similar to the sound in this YouTube video
https://youtu.be/nF3wfjh6chY

I'll do some more tests tonight on the drive home to see if the same noise occurs coming to a stop when the transmission is in N, or stopping in reverse, or stopping in a curve.

In the mean time appreciate any feedback.

[poiuytre111]

There was a similar thread recently where the issue was a bit of slop in the splines of the drive between CV to wheel hub. Removed, cleaned, greased, reassembled and it went away.

[SwissXC90]

Guess what?

Drove home, 30min, motorway and city, and no noise from the brakes at all.

Did some test stops on my quiet street with the window down, nothing.

I'm wondering if a stone was caught somewhere and has since been dislodged.....

[Harley Dave]

Lets hope that's all it was

Cheers

Dave

[SwissXC90]

After 3000km Summer holiday on some rough UK roads I heard the clonking again occasionally, and now the wheel alignment is way out.

Going in for a wheel alignment next Friday and I'll try and look at all the bushes when it is on the lift. Maybe I'll see something.

Hoping it's not CV joints...

[gmonag]

Also consider the subframe bushings. I had an intermittent knock which I cured eventually by fitting subframe bush inserts.

[SwissXC90]

And lower control arm bolt tightness, I just read on another post

[Danielpsmith]

I had something very similar it turned out to be the Brake pads moving slightly I had fitted genuine Volvo ones but a few thousand miles later they were knocking very slightly at low speeds changed them for ferodo ones and been silent ever since

[colinbos]

Don't you just love the Clunks and knocks of our XC90s !

[doingitsideways]

Originally Posted by colinbos

Don't you just love the Clunks and knocks of our XC90s !

Something like that.

I've just changed both front wishbones and ball joints but it's still there!