The flare connectors on Toyota fuel filters are well known to be occasionally difficult, or even impossible to loosen without damage. A dealer will usually ensure they have a replacement fuel line on hand in case the inlet side is damaged on removal.

 

i better leave these kind of "problems" to skilled/ experienced technician. it gets extremely dangerous when fuel messing around

 

Couple things I guess I'll add... Technically, if you open the fuel cap, you are not creating vacuum as your opening up the fuel system to atmospheric pressure (not vacuum). It is very difficult to be able to work this rusted connections, which in Minnesota, I don't care what your drive, any fuel line fittings underneath the vehicle are rusted. The best thing to be able to free up the lines is heat, I have never used a torch, nor would I encourage anyone else to, but there are many alternatives that can be used along with some sort of rust penetrant. The best thing to do would be to obviously drain as much fuel out of the tank as possible, however as a service tech, you don't always have the option to drain 20+ gallons from the tank. Although most people don't have access to the plastic/rubber line caps, those will often work the best from dumping all the fuel out.

 

These are good tips. I'll remember them for my imminent fuel filter replacement.