Why do the three part filler caps have three parts? What is the screw for, apart from keeping the internal bit of metal in place or is that it? Are they better than the one piece caps and if so, why? I've just acquired my first 3 part filler cap device and I'm curious.
Yes as simple as that. The idea was that when tightening the inner part did not turn so the rubber didn't scrub and wear. ::Neil::
The three--piece caps allow you to tighten the cap without abrading the gasket by twisting it against the fuel bung. A pretty good idea, really. It's much easier to replace a gasket on the three-piece caps, too. Just tighten the cap on the bung, unscrew the screw and remove the insert. Place the insert on something flameproof and burn the old hardened gasket out with a propane torch. Let cool, scrape out the residue and Bob's yer uncle.
As Hippie said, a really cool way of sealing the cap to the fuel bung without distorting or tearing the soft seal. Works great and easy to change.
I agree to all thats been said, i love the three piece caps just on each of changing out the gasket when needed
