god dam fuel connectors!!

Does anyone have any idea how to get the fuel connectors off??? You know the type, they are basically a large lump of hard rubber around the fuel pipe with two flats on either side which ,when pressed, go into the pipe , which I assume is how you get them off! I have tried and tried , but no luck. Do you think I need a special tool for removal or is it just a question of brute strength! The pipes in question are on the fuel cooler matrix, which are attached right next to the engine. There are two pipes , one is a normal squeeze in clip(easy) and the other is one of these nightmares! Why that is i do not know, can anybody help because I need to get the cooler off to have it fixed and i cannot drive until it is sorted. Cheers Paul