When I got back from picking up a load of alfalfa today, I noticed a good amount of oil on and around my AC Dual fuel pump. The oil appears to have leaked out of the top left hole ( two holes at the top ). Does this indicate a failed or failing diaphram in the dual fuel pump? It appears I did not loose that much oil , checking dipstick. Is this common? The fuel pump was rebuilt 4,500 miles ago or roughly 4 years ago. Still runs like a champ! See attached picture taken later after I found the leak. Todd OK, Draft tube cleaned. After 50 miles today the fuel pump is still weeping a little oil out of the hole. Not as bad as last time. Rebuild the fuel pump?
Check the crankcase ventilating system for restrictions- - - -like a sludged-up road draft tube, for instance. I believe that there is a deflector around the fuel pump operating lever that's supposed to prevent oil leaks from those vent holes, but a clogged crankcase vent system will find a way to vent the fumes and pressure elsewhere. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Can't answer your question exactly, but I've also fought a small oil leak from my single action glass bowl type. Not sure where on the pump it's from, exactly. Replaced gasket and used ultra black (which I ordinarily wouldn't use). The two flange bolts are also hard to get a wrench on to fully tighten.
Matthew 6:33
1952 Chevy 1/2-ton 3100 Late '55 235/SM420/torque tube 3.55 Dalton Highway survivor (using original 216) www.truckwithaheart.com
Airtex fuel pumps on my Ford pickups were extremely bad about the diaphragm tearing and blowing oil out the vent hole.
Take your pump apart and look inside.
1950 Chevrolet 3100 (Ol' Roy)
1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)
I've seen road draft tubes that have never been cleaned and they still function to some extent, so it's unlikely that there's a problem with one that's been serviced, ever. Just one thing to check off before digging deeper into the problem. I like to soak a draft tube in gasoline or Diesel fuel, and set it on fire, then after it cools, tap it repeatedly with a hammer and shake the ash out of it. It's surprising how much crud comes out after doing that. Chances are the problem is in the pump itself, but you know what "assuming" makes you and me! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
OK, Draft tube cleaned. After 50 miles today the fuel pump is still weeping a little oil out of the hole. Not as bad as last time. Rebuild the fuel pump? Todd
Any idea about total mileage since the most recent rebuild? Excessive blowby can push oil out of places it isn't supposed to go- - - -like a fuel pump vent hole. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Well, that pretty much cancels out the "worn out engine" idea! It sounds like it might be time to send a pump to one of the pro rebuilders that other stovebolters have had good results with. I also started a thread about adapting a GM Diesel engine belt driven vacuum pump to a stovebolt engine, instead of fooling with one of the notoriously expensive and unreliable double action fuel pumps. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Then & Now Automotive rebuilt mine about 6000 miles ago. They also rebuilt the one in my '56 Coupe de Ville.
Just FYI, it's widely known that new fuel pumps for virtually every make and model are absolute junk from the get go. Friends in my Cadillac circle send brand new fuel pumps straight to Terrill Machine in Texas or Then & Now in Massachusetts to be taken apart and rebuilt.
The problems range from incorrectly installed valves, poor quality diaphragms, incorrect spring tension, and incorrect throw of the lever arm.
Last edited by Gdads51; 02/18/20263:06 AM. Reason: update to new web address
1950 Chevrolet 3100 (Ol' Roy)
1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)
Otto, I agree on off the self garbage in last 5 years! 100% Then & Now rebuilt my dual fuel pump 4,500 miles ago!!! That is why I am confused at the leak. I will call them and see what they make of it. Thank you, Todd
I see. I'd be interested to see what happens when you talk to them. Maybe they'll send you a new diaphragm.
1950 Chevrolet 3100 (Ol' Roy)
1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)
I will report back with an update. Worse case I buy a kit from them and rebuild it. I have never rebuilt a fuel pump so I am not sure what would leak at that point, diaphram? Seal? It still runs & drives great. Just a slow weep now out of the top left hole. Todd
