Mysterious fuel disappearance in 1959 Fleetwood

[rex]

Hello Group,

I am wondering if one of you geniuses out there can figure out what's wrong with my '59 Fleetwood's fuel delivery.  The car runs perfectly at all speeds and never stalls out EXCEPT in this circumstance.  When I have driven the car some distance and park, after a couple of minutes, I can see the gas literally being sucked out the fuel filter bowl until there is nothing in it.  If it sits in this condition for a while, the car will start and then often stall out. Once stalled,  you generally cannot start it at all again unless you prime the carb with gas. There is no gas in the filter bowl at this time and none comes in when turning the car over. 

I by-passed the vapor return line (it's an a/c car) and installed a new fuel pump, neither or which correct the condition.  The fuel pump cannot pull more gas back into the carb without the help of priming.  Once running again, it's fine until the next time. What's happening??  Any comments will be appreciated.

Thanks,

Rex  #18304

[Walter Youshock]

I had a similar problem on my '57.  First of all, there should be a rubber (fuel resistant) gasket under the center hole of the filter element.  That gasket goes on first, then the element, then the large outer gasket.

If the fuel bowl was overtightened, the pot metal filter body may be distorted allowing air to be sucked in when the car is off.  Remove the filter and gaskets and put the glass bowl on the filter body and rock it in different directions.  If it doesn't fit flush to the body, then you can carefully get it back in shape with a bench vice and some scraps of wood.

[rex]

Thanks for that suggestion.  I am going to check and see if this could be the problem, but it certainly sounds logical.  I'll report back! 

[Walter Youshock]

It's worth a shot.  This drove me crazy for years.

When I gently bent the housing back into shape, I bent it slightly concave where the bracket holes are.  When I torqued it with the bowl in place, it pulled the housing tight and flattened it out again.

[curly]

Gas tank not vented, creating a suction that pulls the fuel back when the pump stops?  Check the gas cap/clogged vent, incorrect cap.

T Lewis

[62droptop]

can you tell if the fuel is being sucked into the carb or back into the tank

i have had fuel boiling in my 62
already been mentioned is a  tank vent issue, as you drive the car may be sucking the tank in slightly due to no vent ,when you shut the car off ,the tank is returning to proper shape

take it for a ride with the gas cap off and see if it still does it
 

[D.Yaros]

I too opt for an improper gas cap.  The tank is vented and modern gas tanks are not.  It needs a vented gas cap.

[rex]

Thanks for your suggestions. Does anyone have a diagram of fuel filter with vapor return line showing the path of travel of gas, vapor, etc.?   There is nothing in the shop manual about it.  I think that something is not pressurizing correctly in the filter assembly itself which creates a situation that under certain conditions the fuel pump cannot overcome.  Thanks!