71 vapour emissions canister/thing under rear wheel well.

[71beeman]

G'day guys,

at the moment I have the fuel tank out, tidying up stuff and waiting for a new sender.

I decided to pull out those vapour lines that are connected to some emissions canister that is located under the drivers side rear guard. I've tried doing a search on the net to find out how this thing works, but there's nothing I'm really after. I'd like to see what the thing looks like inside.

I've tried blowing air through all the hoses and it seems to work....EXCEPT....the line which goes to the engine bay, it doesn't emit any air at all. Surely it's there to relieve pressure, but I can't figure out how if I can't get air out of the thing.

Hope this makes sense. Is it possible to bypass the damn thing, just so pressure can be released ?

Peter

[odzking]

There is an "Overfill Limiting Valve" (that is what the book calls it). 3583538
Do you need it, good question.

[setauketjeff]

A few years late, but I'm new here.   Early 1971 chargers had a pressurized fuel system, later in the year they were not.  Many people make the mistake of using the incorrect fuel cap (pressurized vs non-pressurized).   The valve is used to maintain the proper pressure and stop any backflow.   The metal line returning from under the hood is used to return fuel and fuel vapor back to the gas tank.   It's pressurized from a positive vacuum line out of the carb (vapor too), and vapor return from a 440 fuel filter, as well as positive crankcase ventilation.   This was early pollution control, but also had the added extra of pressurizing your gas tank.   You can easily tell if your tank is properly pressurized, by the gush of air you will get when you release the gas cap. 

[brigond]

Great explanation, thanks this helped me understand the system a little better.
( 2 years later:) hopefully the OP will see this also.

I replaced all the rubber lines with fuel injection line a few years back. Also cleaned up and restored the tank behind the rear drivers sid wheel. (Coated with POR15). Posted it on this forum somewhere.