Rear Knocking/Rattling

[luke.ocana]

I've had some knocking coming from the rear of my polo for a while now. I've had it looked at three times now by independent garages and they've found nothing wrong with it after stripping down the brakes, suspension, checking exhaust and engine mounts etc. They've all told me it's in brilliant condition and nothing is loose or needs replacing.

The car can be fine one day with no knocking at all, then the next day it will rattle like mad when going over even tiny bumps in the road; which baffles me??
Does anyone have any idea what this could be or has anyone experienced this themselves? Before anyone mentions, I've of course checked the interior everywhere for the sound and I can confirm it's definitely coming from outside under the car.

[RUM4MO]

Shock absorbers sticking slightly, what you might call "stiction" the force required to force the rod to actually move in the seal, as opposed to just flex the shock absorber rubber mountings?

[POLO-SA]

The rear shock mounting 6R0513353B was superseded in October 2013 with a revised rear shock mounting 6R0513353. I also had knocks and rattles coming from the back so I fitted my Polo with the revised mountings. No more knocks and rattles when driving slowly over small bumps in the road.