Your hydraulic lines will need to be replaced because it sounds like there's a leak somewhere. Also, the pump is on its last legs, so that should be replaced, too. The shocks have sensors on them which go out all the time and will give false positive readings. The fluid, Pentisone, is as you know very expensive. I've seen pumps go for over $8000.00. The lines to replace are $4000.00 and the struts and shocks are about $1500.00 apiece with the sensors. So, you're looking at a repair bill of $18,000, not including taxes. Good luck.