1983 300D gas flow problems

Hello all,

I seem to be having a problem with the flow of my diesel fuel. The car
will drive really well and then, sometimes, the car will behave as if
it is starved for fuel. Here is what I can tell thusfar...any ideas?

1) it seems to get worse when the tank is low. the problem for me is
that my gauge is funky and so i never really know how full it is. but
yesterday i added plenty of fuel and the car acted up today. then I
added more fuel and it got me home fine.

2) the line going from the big filter downward and towards the smaller
filter seems to be swollen and is a bit soft.

3) the smaller filter, when the car is misbahaving, barely has any
fuel in it. the drips into it are very slow. then, it will fill up
nicely and the car will run fine.

Thats about all I can tell you guys. I have spare filters and can get
the lines if that would help. I want to start with the most obvious
answer before going in deeper. Am I on the right track?

Thanks in advance.

aaron