Rear suspension problems...

My SVX has been in my family for all of its life. My father bought it brand new back in 1994 and I bought it off of him. I have been there through every oil change and seen or done every maintence on it. It has been an unbelievably reliable car. I had a new transmission put in it at 80k and that has been IT!. But, last summer, turning over 120k I thought it was time for some suspension work. So, I had all new OE struts put on and new links and bushings put in. Since then I have gone through 4 struts on the drivers side rear. The car has never been wrecked / no heavy potholes. Every time I get a new strut put on that corner, about 500 to 1000 miles later, it is klunking and rattling like crazy. There are no visible signs of damage in suspension and I have had the car aligned everytime I get a new strut. The alignment shop mechanic does not understand why this is happening. I take the wheel off to find that all the fluid in the strut has leaked out....EVERY TIME!! Does anyone have any opinions? Can anyone out there help me??!!!