Below is a guide to disconnecting those funky garter spring fuel line connectors that hold the pressurized fuel lines to the fuel rail.
Text will be immediately below each photo.

This is the fuel rail out of my '87 TC. They're all basically the same. After relieving the fuel pressure at the schraeder valve on top of the fuel rail, I removed the duckbill clips at the hardlines underneath the car to remove the rail. The connectors can be done in the car, but it's easier with the rail out. Besides, I had to take the rail off anyway.

This guide concentrates on the removal of the supply line. I already removed the return line, but they're exactly the same except for the size of the line. This is the connector in question.

The first step is to slide the retaining clip off. It pops right off with a screwdriver.

Retaining clip has been removed.

Next, remove the plastic clip that covers the actual garter spring. It also pops off with a screwdriver, or it might already be off, or it might be missing altogether! Note I changed backgrounds for better clarity.

Here's the toolset you'll need. It's called a fuel line disconnect toolset. I bought mine at NAPA auto parts for $11. It's got all the sizes you'll ever need - 5/16" to 7/8". There are other sets that cost more and are of better quality, but these work just fine.

This is the actual 5/8" disconnect tool to be used on the supply line. The return line uses the 1/2" disconnect tool. Note the slightly tapered end of the tool that slips under the garter spring.

Open the tool up and slip it over the line and down into the connector.

Squeeze the tool together and push down. You'll actually see and feel the tool sink down into the connector about a 1/2".

Here is the connector already off so you can see the garter spring. When the tool sinks down into the connector, it's actually slipping underneath the garter spring.

When the tool slips underneath the garter spring, it's opening the springs circumference wider than the lip on the rail itself, allowing the spring to slide over the rail lip. The spring acts like a clip over the lip of the rail, to hold the fuel line on.

Now comes the tricky part. You have to squeeze, push down on the tool and pull down on the connector at the same time (it helps to have an extra set of hands)!

There are 2 o-rings that seat the connector/fuel line into the fuel rail. If the fuel line has never been removed, it's going to be seated in there pretty good. It may take a little effort to break it loose. Just keep trying and take your time.

Here's the fuel line removed. That's all there is too it! Pretty simple, huh?
STANDARD DISCLAIMER:
This is only a guide. I am not responsible if you screw up your car or sustain bodily injury. Use at your own risk! There, you can't sue me now!
Good Luck