This is the tool I used, a K-D 3321, available at various auto parts stores
for around $12. Use the smaller 5/16" end.
This is what things look like before you start. Note the safety clip on the end of the fuel line where it mates to the filter. Remove this by squeezing it together and unhooking the small latch. Your new filter comes with new clips, but I prefer the factory issue as they're somewhat sturdier so I always save them.
After you've removed the safety clip, slide the fuel line away from the filter so you've got enough room to insert the tool. On this particular vehicle, one of the fuel tanks
interfered with my using the tool, so I had to slide the filter partially out of the bracket to gain access. No big deal. Push the tool in to the fuel line (away from the filter) and listen/feel for a click to indicate you've disengaged the locking device from the filter
Once you've disengaged, pull the line away from the filter. At this point you'll start getting some fuel draining out. I like to take the dust cap from the new filter and place it over the discharge end of the old filter to control the mess. Try to move the fuel line so that it's raised to minimize fuel leakage from there as well.
I'd like to pause right here and re-emphasize safety. I was not wearing any eye protection when I started this. That was extremely foolish of me and I paid for that oversight when a small amount of gasoline splashed in my eye. I had to stop what I was doing and flush the eyeball. NO SHORTCUT IN THE WORLD IS WORTH YOUR EYESIGHT OR SAFETY!!! I was lucky and didn't cause any serious injury to myself, but it did burn like heck. SAFETY, SAFETY, SAFETY!!! I CANNOT EMPHASIZE THAT ENOUGH!!!
I then moved on to removing the fuel line from the inlet side of the filter. Everything that was said earlier applies here, too.
Here's the old filter, disconnected and ready to come out.
Here is a view of the locking device within the fuel lines. Note the "teeth." These are springs that lock on the raised flange of the fuel filter . When you insert the tool to disconnect, you are pressing in on these springs
When you're ready to install the new filter, insert it into the bracket and press the fuel lines on to the new filter. Just as you felt/listened for a click when removing the fuel lines, listen/feel for a click during installation
After you've hooked the fuel lines to the new filter, install the safety clips and you're done. It's that easy.