I have a 49 Pontiac with the straight 8 and auto trans. My fuel pump is current leaking out of the top gasket. My questions is, I have the double diaphragm fuel pump, am I able to swap it to the single diaphragm fuel pump till I get the double diaphragm rebuilt? Thanks guys.
I suspect the second diaphragm is for a vacuum pump if the vehicle is equipped with a vacuum powered wiper motor. The single diaphragm pump will likely still work to supply fuel to the carb, but you may lose some or all functionality of your w/s wipers depending on how the existing vacuum hoses are routed. Depending on how your old pump has failed, it may be allowing fuel to get into the crankcase. Check to see if your oil seems too thin or smells excessively of gasoline, or looks over-full on the dipstick. If so, plan on an oil change before driving it with either fuel pump.
Yeah, I've read it powers the wipers, but I don't have any on the car, just an old hot rod to cruise with. And it was leaking out of the top, none got into the crankcase. I have another question as a newbie hear, the other line runs into the intake below the carb, will I need to block that off because of a vacuum leak, or am I good?
Yep. You'll want to plug off any vacuum hoses that ran from the pump to the engine. If it was me I'd want to plug it with a vacuum gauge mounted in the vehicle. But I'm funny like that about vacuum gauges. If you don't have any other vacuum powered accessories on the car you could probably get by with just running the single diaphragm fuel pump.
It's been a while since I have seen one, but I recall that that fuel pump is the same as Chevy 6, Pontiac 6 and Olds 6.
The Jalopy Journal
