Why are my vent lines leaking?

[DynaBro]

70 Super Bee. Vent lines at the tank will not stop seeping at the tank junction. I replaced both rubber hoses and all 4 clamps. They are tight. They are fit correctly. I have no idea why they will not stop seeping fuel. The longer line is properly run through the trunk. But I do occasionally hear that wheezing sound. Did I overfill the tank prepping for winter somehow?

 

[4mulas]

Is ut an aftermarket tank? Often the vent tubes are reversed in the tank. Got lost in translation over the years. Search to forum, there is good info on that.

 

[DynaBro]

Is ut an aftermarket tank? Often the vent tubes are reversed in the tank. Got lost in translation over the years. Search to forum, there is good info on that.

I can’t be certain but highly doubt this is a replacement tank.

 

[T2R9]

What gas cap is on the car?

 

[dfrazz]

What gas cap is on the car?

^^^^ This - make sure sure your cap is vented

 

[DynaBro]

Here's the cap. Appears to be non-vented. Also pics of the problem area. The right one is leaking the worst and it vents through the trunk. The left one is a return line to the fuel pump stuff. I don't understand why this is doing this. Fresh rubber. Fresh clamps. New carb. New line from the carb to the fuel filter.

 

[DynaBro]

I read a lot about vented fuel caps just dumping fuel from sloshing around. No? Anyone have the correct part number for a 1970 SuperBee cap?

 

[Runner 68]

Does it only leak when the tank is super full?

 

[DynaBro]

Does it only leak when the tank is super full?

I don't think so. The smell has been bugging me since I got it and it's been as low as half.

 

[Runner 68]

I have had a similar problem but only when its full-full and has sat for a while. Non vented cap here but two large 1/2" "custom" vents coming out the top of the tank.
Can't figure it out. I have just made a point to fill it only to 7/8 of a tank.

 

[DynaBro]

I keep reading about the lines being reversed on after market tanks, but if I pull these I am going to get fuel all over the place again as the tank is full full. And it would just be to swap them ASSUMING that would be the case. And now it's snow and ice so I can't even wash the mess off properly. Don't have any ability to see inside the tank now that it's full do determine if it's an aftermarket with reversed inner lines.

I also read that this cap would work https://521restorations.com/Gas-cap-vented-for-73-74-B-Body/

 

[DynaBro]

And now I am wondering why my car has a return line.

 

[kiwigtx]

I would guess that the vent lines are blocked, and the tank is pressurising due to the non-vented cap.

The return line from the breather at the front is likely blocked off also.

 

[DynaBro]

I would guess that the vent lines are blocked, and the tank is pressurising due to the non-vented cap.

The return line from the breather at the front is likely blocked off also.

Why would the tank be pressurizing while parked in a cool environment?

I'm assuming there's no clean and easy method of checking for line blockage?

The return goes to the front and is hooked up in pic.

 

[4vnut]

Check the nipples themselves for pinholes from corrosion. I've seen it happen, to me.

 

[DynaBro]

I’m getting the impression a lot was done to deal with vapor lock? A return line, running off both the pump and a 3 nipple filter. That’s not very common is it?

If this were also kicking gas all the way into the vent line that runs through the trunk where would I be seeing the drip? I looked all around where I see it leading out but can’t find the end.