Problems with water in Hymer B654 (1994)

Hi everybody,
As a full-time volunteer aid worker in Romania I picked up a Hymer camper last year because of health problems. I need to stop every 3 hours or so as a result of a massive lung emboli followed by removal of a kidney due to cancer. Whicj also means that my power to work on things is very limited.

Last year I already noticed that the water came slowly and irregurlarly from the different faucets, now it's much worse. The shower head and toilet have virtually given up, the bedroom faucet only works sometimes when the kitchen faucet is in use and the kitche faucet now works fairly irregularly.

First I checked the water pump, which seems to work with sufficient power (1,2 bar is written on it). Then I found the distribution point in the back of the camper and found out that the water there comes out full power. then I checked the line to the kitchen and to the shower and there too I found no problems.

So I'm at a loss as to what to do. I have no idea at all about how to disassemble the various faucets and in fact I don't even know if they could be the cause. In the faucet filtres I found some sticky lime but that was easy to remove because it hadn't hardened at all. Theoretically in the faucet mechanism there could be some form of obstruction, but only when using the present pump. My brother put 7 bar pressure on it from the distribution point in back and that produced a perfectly straight line of water until the tube was empty.

Could it be that the 1,2 bar pump somehow isn't good enough anymore? There is no dirt whatsoever in the pump or in the lines at all. Or should I try to somehow disassemble the faucets? What is the max power in bar that sould be used in a water tank like mine?

Thankful for any suggestion!

Paul.