If the tension discs are not lifting with the presser foot lever up, then I would look at two things: 1. the lift lever underneath the nose plate; I have had it where the screw holding this in was loose and the lever would not function properly; it also has to seat properly on the left block over the presser foot lift lever; when I have had presser foot bars out it's a bit of a trick getting it all back together to lift properly; 2. the lift rod inside the tension assembly shaft could be stuck, or maybe in backwards; remove the entire assembly, disassemble, and see if the rod comes out; I had one of these sticking once and sanded it off with polishing sandpaper. I also lost one of these rods under the workbench and had to substitute a clipped off finishing nail; I finally found it again.