3 Volvos. Today I am working on 1985 240DL

My 240DL wagon has been one of the most reliable cars and certainly one of the most fuel efficient. I gave it to my son, and it came sputtering home one day, stalled in front of the house, and we had to push it up into the driveway.

Now I am working on the fuel system. I disconnected the fuel line behind the fuel pressure regulator. At first, I connected power directly to the in-line pump and fuel gushed out at the disconnect near the fuel pressure regulator. It doesn't do that anymore. I installed a new relay, new fuse and fuse holder near the power steering fluid tank, checked the fuses in the panel, installed a new fuel pump and filter, and I am currently attempting to replace the in-tank fuel sending unit. I am stuck because I can't get one of the hoses off the sender's nipple, so I can't lift it out. The fuel hose to the main pump came off. It is the other hose that seems to screw into a hexagonal metal fitting at the other end that won't come off the sender nipple. Can anyone give me any hints as to how to remove this supple hose that may be a fuel return line?

Ultimately, I suspect that I have removed the main pump/filter unit so many times that the fuel lime may have become kinked and no fuel can pass through it. How can I test it? What should I look for? Can it be patched? Or will I have to replace the entire fuel line? If so, where can I get an entire fuel line for a 1985 240DL wagon?

By the way, in case anyone asks, I replaced the main engine wiring harness about 6 years ago. That solved many miscellaneous minor problems.