Technical gas tank install - flex line?

I'm installing a gas tank from one of the popular manufacturers for the first time and they're suggesting that I use flex line between the tank and where the hard line runs along the frame. Is this common, recommended? I'm installing the tank under the bed of a '51 F1. There's nothing extreme about this vehicle (not race or off-road or anything) so I'm not sure why this would be necessary.

Any thoughts?

thanks

 

Yep that works and is common. The flex line in question is pretty short.

 

With this universal tank, the connection to the pick up tube is going to end up near the middle of the vehicle (side to side), so I'm going to need about 2-3' of rubber hose for this.

 

well then you need to get a longer hard line.

 

No you bend your hard line up to the top of the tank and you need about 2 or 3" of flex or else use steel braided tubing.

 

A little more expensive...but...I ran Teflon braided line and stainless fittings from the tank to the carburetor in a car I'm rebuilding.
That way, I'll never have to worry about the amount of alcohol in the gas... No steel or aluminum lines to corrode.

In any case, while it is needed for frame flex, never run more than a few (5 or 6) inches of rubber line. Just being safe, as most people never check that line till it's too late (leaks)..!

Mike

 

Why is it ok to use 2-3" of flex line, but not 2'? I've always wondered why everyone says your car is fixing to blow up with that much rubber hose! Is it because of vibration and chaffing of the hose, or???

 

Easier to use a short section of hose rather than a long section. Tank outlet is secure as is end of hard line with short section of flex line. You don't need 2' of flex line unsupported. Standard practice. If you decide to use 2' it needs to be properly secured all the way and not hanging as it could eventually fail at last attaching point due to vibration and being unsupported. Remember it will move around as the car is driven. As a rule of thumb lines are secured every 12"

 

Thanks for the advice guys

 

Nothing wrong with rubber hose if it is the correct type. High pressure for FI with pump in tank, is a good idea any time.

Old cars had solid steel from tank to front of car, starting in the sixties they used a short piece of rubber at the factory, mainly for easier installation. Chrysler products had a tin piece that clipped on both steel lines, bridging the rubber part, to guarantee a ground for the fuel gauge. The tank must be grounded or the gauge won't work.

All cars had a flex line between fuel pump and frame, from the time they started using rubber motor mounts. There is nothing wrong with rubber in the fuel feed line.

 

I use that short section of flex line to add an in line filter at the back but before the mechanical pump, and another one before the carb.