Fuel tank vent

I have been reliably informed that the fuel tank and carbs are vented via the side vents at the rear of vehicle.
As our bus had, well, pretty much nothing with it :

A : is this correct?

B : could I not "vent" the floor where the tank resides instead of making / sourcing these pipes?

C : if the answer to B is no, then what would be the best way to do this - have no carb set up on engine, could I use silicone pipework or would it have to be of the metal variety?

D : would anybody have pics / diagrams / etc of how this pipe is run, etc?

Thanks all

 

This diagram shows the layout of the breather system.

 

Cheers @Iain McAvoy

Can I ask where the diagram is from - just need to look at the numbering legend.

I'm assuming I couldn't just vent the floor then?

 

I think what was meant was the fuel tank vents through the carbs or at least the air filter via the vents at the side of the bus!!

 

Via the air filter? Mine is going to RHS of engine with intercooler

Only found out about this yesterday so I'm totally blind on this one. I'm also replacing the fuel tank floor so any help would be appreciated.

 

I got it from Mayor Ratwells site http://www.ratwell.com/technical/FuelHoses.html

 

Mayor for how long, I wonder?

 

From some of the things I've read, not for much longer.

 

@3TNC if you look at @Iain McAvoy 's picture the pipes I was talking about are 10 and 10a. You can see the bulges which are level with and inside the side vents. As I understand it the bulges are to help prevent syphoning and allow the fuel in the air to condense and run back into the tank.
I think you should be able to get all these vent pipes off of a scrap bus easily enough.

 

The diagram is from VW's Bay window parts microfiche that the dealerships had back in the day. The numbers on the diagram would then be listed to the side of the diagram with the corresponding VW part number along with the years/models it applied to.

 

Hi bud,, this is what it looks like inside from a 72 I broke up.

Ozziedog,,,,,,,,,,,,,,,, I didn`t mean too

 

Think the P/O has probably thrown them away aswell

 

If they're there you should be able to see them through the air intakes on the side of the van.

 

Rear panels were replaced and most of the original bits were thrown - including the 2.0 air - hence the question of can another method be used instead of running vent pipes

 

I too have the same problem. Is there an alternative to using the original system?

 

An alternative could be to drill a small hole in the filler cap so fumes vent to atmosphere – but it won’t work anywhere close to how VW intended. Replace what VW fitted if at all possible; they did it like they did because it works rather well.

 

I think having the tank right next to the hot engine means the fuel evaporation rate is a lot greater than on most vehicles. It's one reason our buses are prone to engine fires. It needs the proper venting kit.

Also from the way my system gurgles after a run I suspect without the condensing bulbs you'll be venting a lot of fuel straight to atmosphere.

 

Or worse still spitting petrol out of the tank vents if you dont fit something that goes little pipe big pipe little pipe high like the condenser bulbs up so vapour can bubble through any petrol that goes up the vents from the tank top and then then petrol gets sucked back down when it cools.