You might need to cut the steel line and flare it for a new fitting. If it is low pressure than you can get away with using a barbed fitting and hose clamps to secure the new rubber hose. Make sure you buy fuel rated hose. It is probably 3/8" or maybe 5/16".

 

I think that the return line is 5/16".

 

Anyone know what sizes all the fitting are like on the fuel filter, tank and braided lines?