Nope, it'll only stop leakage at any splice, which is what I thought was your problem. If it's 'pumping' over the top of a high vent, check your routing, any low spot will effectively shorten your vent, reducing vent hose capacity, allowing quicker overflow.
I extended the fuel vent on my Talon to the front but it never gets higher than the radiator overflow cap (just below the hood). If heat causes the gas to expand more than the height can control, I'll get a little fuel dripping out the vent (which is under my winch). That's a rarity because there's an air bubble at the top of the tank and fuel shouldn't be able to get up to it. Note that this only happens with a very full tank. If the sleeve has been removed from the tank fill tube, this leakage will be worse because you can overfill the tank. I've done this mod and accept the resulting leakage.
