Loop on fuel pipe on ford f15 ...f60
 

Hello

Rebuilding my truck I would know the aim of the loop made on all fuel pipes (The twice linking the fuel tank left and right to the fuel switch, the the one from the fuel switch to the fuel filter and endly from the fuel filter to the carburator.
On US vehicle like DODGE or GMC we don't find these loops.
Thanks for any answer

The loop or pig tail in the line is to allow flex with the vibration created from the engine, driving etc. with out this loop/pig tail the line could crack or break.

Neil

If you keep that loop going uphill all the way you'll have less chance of yapour locks.

Problem of dilatation or retraction
 

Hello

After having read the answers to my question about loop on fuel pipe, I have spoke with a friend who works in nuclear domain.
He explained me that the aim of the loop on fuel pipe was to compensate the dilatation of the iron. In NORTH AFRICA we have to "play" with a difference of at least 60 degres CELCIUS between a hot day in the desert under the sun and the coldness of the night. I think that it's explanation should be right

Regards Serge

Serge
 

Your second photo also shows the body mount, where movement is allowed to happen. This loop is all about allowing for the movement between the frame and the body, when the chassis flexes on rough terrain.