I have a similar problem. knocking noise at the rear,
but when the car is full of passengers, knocking stops...
do you think it is also in this case a problem in broken shock absorber?
On my car I had the same symptom driven me crazy.
*Check if the connecting bolts on shock-absorbers (upper&lower) are tightened properly. You need an assistant to "swing" a chassis up&down. It's easy to check/access lower bolts from beneath a car. Upper bolts are hidden below rear wheel-vane protection which has to be slightly removed to provide access to upper bolt(s).
* It's necessary to provide a wrench 22/12-angle and good wrench/rachet 1/2". At least on my scenic it was; The best solution is to have torque-wrench but it's not obligatory;
If that's a case, when you locate a loosen bolt, do next:
- slightly lift-up one rear-wheel so you can move wheel-vane protection to access upper bolt
- lower the car completely on ground (release lift) and tighten upper bolt with 22/12ang firmly
- lift again and put back protection
- put down the car;
Repeat if necessary on other side. Do it ASAP because if that's a case, soon it can lead to bigger damage(s)
Wheels should not be removed and when tightening bolt(s) wheels must be on ground!