Why does my 1970 oldsmobile F85 have 4 lines coming off of the gas tank ?

 

Welcome.

Its part of a system that includes a stand pipe and charcoal canister for recovering fuel vapors.

Its a good idea not to modify these things. If you have any cracked hoses it is a good idea to replace them.

Here is one link that talks a little about the stand pipe. Don't let the title throw you. You can search for more on the charcoal canister as well. This will at least give you an idea if you don't have a factory manual....its all in there. If you have an old car, you need one.

https://classicoldsmobile.com/forums...t-working.html

 

So it can go four times as fast.

Welcome to ClassicOlds.

- Eric

 

Could I cap those lines off and use one line for fuel to engine driven pump and is the other line a bypass line from the fuel pump back to the fuel tank ?
Just got my 1970 F85 and nothings hooked up right

 

I wouldn't do that. If its just temporary maybe yes if only checking other stuff.

 

Tell us what your doing. Like whats going on with the old car?

 

Sure you could. You just have to be sure you've got a way for air to get into the tank.

The original setup served this purpose well, so the best thing to do would be to fix whatever's broken.

- Eric

 

And so basically the 2 extra hoses are basically vents? That could be tied together and put a small filter on ?

 

I suppose.

Why not read the section on the evaporative emission controls in the Chassis Service Manual?
That way, you can make an informed choice.

- Eric