fuel vent separator

[scottyrocks]

I am preparing to put a new fuel tank into my '73 Mustang.

When I took the fuel vapor separator out of the old tank, some black stuff fell out of it. When I touched it, it crumbled. What material is it? Is it necessary?

I ask is because when I was inspecting the unit, it appears that the metal tube that comes out of it, that the rubber hose from the charcoal canister (?) connects to, has no opening at the other end, inside the unit. I stuck a small wire in it to see if would go through where I couldn't see, but nothing.

What is the purpose of having a tube that goes to a dead end in a fuel tank? Or is mine just somehow jammed solid at the inner end with dirt, maybe?

 

[OMS]

I am preparing to put a new fuel tank into my '73 Mustang.

When I took the fuel vapor separator out of the old tank, some black stuff fell out of it.  When I touched it, it crumbled.  What material is it?  Is it necessary?

I ask is because when I was inspecting the unit, it appears that the metal tube that comes out of it, that the rubber hose from the charcoal canister (?) connects to, has no opening at the other end, inside the unit.  I stuck a small wire in it to see if would go through where I couldn't see, but nothing.

What is the purpose of having a tube that goes to a dead end in a fuel tank?  Or is mine just somehow jammed solid at the inner end with dirt, maybe?

It has a small hole get a wire and clean it out

Replace the material that is crumbling with some stainless steel steel wool

 

[c9zx]

Excellent idea Don! Chuck

 

[rackerm]

I am preparing to put a new fuel tank into my '73 Mustang.

When I took the fuel vapor separator out of the old tank, some black stuff fell out of it.  When I touched it, it crumbled.  What material is it?  Is it necessary?

I ask is because when I was inspecting the unit, it appears that the metal tube that comes out of it, that the rubber hose from the charcoal canister (?) connects to, has no opening at the other end, inside the unit.  I stuck a small wire in it to see if would go through where I couldn't see, but nothing.

What is the purpose of having a tube that goes to a dead end in a fuel tank?  Or is mine just somehow jammed solid at the inner end with dirt, maybe?

Yea, mine looked black inside too. I just took the ring off and cleaned out the black and brownish stuff. It smelled pretty bad. I think I use a small drill bit and twisted it by hand to clean out the tube. I used a course lawnmower air filter to replace the mesh material inside. I figured it was gas resistant.



how to host an image

 

[secluff]

scottyrocks, you've discovered something a lot of folks have found when pulling the tank on these 40+ year old cars. The black material is what's left of a open cell foam. That foam material was used to permit fuel vapors to pass through the vapor separator valve  to the charcoal canister but to keep liquid fuel from entering the orifice and possibly stopping the line up and not allowing the fuel system to vent properly. I believe some of our forum members have used something similar to steel wool which would provide the same function as the original foam.

The orifice is small so you may need to try a smaller diameter wire or try some compressed air.

 

[scottyrocks]

Fantastic! Thanks for the quick, on-target responses! I'm gonna get on this right away.

 

[Jeff73Mach1]

I'd replace the guts with stainless steel cut from a choreboy pad. It is more of a flattened ribbon and if it should ever deteriorate, it would not make it through any filter.

 

[scottyrocks]

I replaced the filtration medium with a small bit of stainless steel wool. The new tank is undercoated and the separator and sender units are back in place.

The only thing I have left to do before installation is to blow out the line that connects to the separator.

I have been under the car and in the engine compartment countless times already but I cannot determine where this line enters the engine compartment, as it passes into the chassis from under the car. There's a lot of stuff coming through the firewall. Any help? A picture with an arrow pointing to what it connects to in the engine compartment would be best. Thanks.

Edit: I looked in the engine compartment again, and took a guess as to the most likely line.

The entire line, from the back to the front where it disappears into the chassis, is steel. I located a steel line of the same OD coming out of the firewall on the driver's side, and then cross to the passenger side, rising slightly.

This line, on my car, is capped off with a piece of 3/8" rubber line, with a bolt in the other end.

I placed the air hose on the end of the line by the tank, and blew the bolt out of other end in the engine compartment.

So now my questions are, why have a vent when the other end is closed? Should it be connected to something? Or is the volume of the entire line enough to do the job the vent was designed for? Thanks.

 

[Stanglover]

I know yours is a 73, but maybe this pic of my 71 vent tube and charcoal canister might give you an idea. I believe the 73 canister is mounted higher and a different shape/size. The attached pic is from before I redid the engine bay, but I think you can see what I mean.

Also, did you happen to see my previous post on replacing my fuel tank, lines, pump, sending unit etc. etc.? Not to worry you, but this is what an old steel fuel line can look like. I replaced with SS.

 

[rackerm]

Here is 73 charcoal canister and lines. I a have spare if you need one.

https://ibb.co/nf9OhS

 

 

 

 

[scottyrocks]

Yep, I found my charcoal canister. I guess a PO felt that just plugging the line was a better option. Right now it's just open to atmosphere.

So now the entire fuel system is back together. I put 5 gallons of gas in the new tank, and nothing is running out of the fuel line when I disconnect it from the pump. Shouldn't the weight of 5 gallons of fuel cause it to flow out that end of the line? Or does the raised portion of the line in the front wheel well overcome that?

Anyway, I just now replaced the battery cables, as the battery charger wouldn't even acknowledge that it was hooked up to anything and wouldn't take a charge due to the original (?) lines being fahshit. The battery is charging as we (I) speak (type).

If I get confirmation that gas is not supposed to flow out of the disconnected line at the pump I can proceed with a clear head.

 

[scottyrocks]

Duplicate deleted.

 

[midlife]

For the most part, gas is sucked out of the tank by the fuel pump. The pickup tube extends down into the tank below the level of the connector on the tank itself. You'll need enough gas in the tank to be higher than the highest point of the pickup tube or anywhere else along the line for it to come out due to gravity, assuming there is a vent to allow air to fill up what gets spilled out. If no vent, you'll induce a vacuum preventing gas from running out due to gravity.

 

[Stanglover]

+1 on Midlife's comment.

Funnily enough, I pondered this very question when I was replacing my tank and lines. Why does that supply tube take a detour up and through the apron, then back down again to eventually re-enter the lower front apron and to the fuel pump?? It would have been far easier to have kept it on the outside, but it would still need to go over the suspension. I posted this question and one response was that the fuel pump (?) on the inline 6 was located just under the hood spring. I'm not sure about that, never seen one, but my conclusion was that the line needs to go higher than the tank in order to prevent back-flow, thereby keeping fuel in the line at the pump.

No fuel leaked from the line when the line was removed from the pump. As I've said before and it's controversial, I place a steel  inline filter between the apron and pump, you've seen the picture of the rusted fuel line I'm sure (and that was a good part of the line), to stop crud getting into the pump. I experience no issue with fuel flow to the carb under heavy acceleration on the stock M code motor. I will irritate the need for ETHANOL resistant rubber lines be used on all connections. High pressure fuel injector hose is what you'll need, but it ain't cheap!!

Geoff.