51 8ba fuel pump woes

Steve51

Steve51

Member
The fuel pump started leaking at the diaphragm and after removing it I noticed the mating surfaces were not ideal. O took 220 and 400 grit sandpaper on a flat surface and much improved the surface to the point I can hold up the pump haves together metal to metal and see no slivers of light between them. No leaks now but it won't pump. The diaphragm while not new is not cracked and does not leak into the lower chamber...it does have an extra set of holes due to the offset alignment of the connecting rod. There seems to be plenty of up/down movement of the diaphragm and the engine was rebuilt under my father's ownership several years ago so a worn pump pushrod is not a main suspect. The small outlet valves passes air in both direction so I would say that is bad. The inlet valves only passes one direction.

Would a bad valve cause a total failure of the pump?

The pump on the car is stamped made in Canada. A friend gave me a pump stamped made in USA. The Canadian pump on the right has the six threaded holes symmetrical with the centerline of the pump and has a smaller glass bowl. Looking closely you can see the USA pump on the left the holes are offset from centerline. The pump lever is also different with the USA pump having a bronze bushing...they are the same otherwise. The diaphragm spring also came with a rubber seal on the USA pump and the diaphragm is a heavier rubber material and not cracked but is harder to work the pump by hand. All the parts mix and match even with the offset holes but still no joy. Yes, gas in the tank, the line is clear as I can blow through and make bubbles in the tank. I do have a rebuild kit on the way.

What is a good way to remove these two small valves?They are the pressed in ones.

The two pumps also have different size in and out threaded ports. So what do I have here....pumps of different years, a truck or Mercury pump?
 

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Steve51 said:
The fuel pump started leaking at the diaphragm and after removing it I noticed the mating surfaces were not ideal. O took 220 and 400 grit sandpaper on a flat surface and much improved the surface to the point I can hold up the pump haves together metal to metal and see no slivers of light between them. No leaks now but it won't pump. The diaphragm while not new is not cracked and does not leak into the lower chamber...it does have an extra set of holes due to the offset alignment of the connecting rod. There seems to be plenty of up/down movement of the diaphragm and the engine was rebuilt under my father's ownership several years ago so a worn pump pushrod is not a main suspect. The small outlet valves passes air in both direction so I would say that is bad. The inlet valves only passes one direction.

Would a bad valve cause a total failure of the pump?

The pump on the car is stamped made in Canada. A friend gave me a pump stamped made in USA. The Canadian pump on the right has the six threaded holes symmetrical with the centerline of the pump and has a smaller glass bowl. Looking closely you can see the USA pump on the left the holes are offset from centerline. The pump lever is also different with the USA pump having a bronze bushing...they are the same otherwise. The diaphragm spring also came with a rubber seal on the USA pump and the diaphragm is a heavier rubber material and not cracked but is harder to work the pump by hand. All the parts mix and match even with the offset holes but still no joy. Yes, gas in the tank, the line is clear as I can blow through and make bubbles in the tank. I do have a rebuild kit on the way.

What is a good way to remove these two small valves?They are the pressed in ones.

The two pumps also have different size in and out threaded ports. So what do I have here....pumps of different years, a truck or Mercury pump?
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The early pump has a tapered seat on the bottom of the in/out ports and uses a straight thread. Later pump is NPT thread. When you rebuild you do not want the operating arm to wobble back and forth on its retaining pin and between the casting. I see two of the three piece operating arms but do not see any of the smaller springs to return the arm.
 
Not sure why folks immediately say send yer stuff to Charlie. I have great respect for Charlie, but many of us do stuff for ourselves.
 
leon bee said:
Not sure why folks immediately say send yer stuff to Charlie. I have great respect for Charlie, but many of us do stuff for ourselves.
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Yeah, I am a DIY guy too. When something fails on the road you can't send it out. If I can rebuild the carb and tune so it purrs I should be able to deal with a fuel pump.I am new to these flathead so not afraid to ask questions.
 
I think the "Send it to Charlie" sentiment comes from the fact that by the time a guy gets his problem to the stage he posts it here, it's at the "wits' end" stage. A lot of the time, It's a good idea to get the car "up and running" properly before frustration sets in. Once the cars "up and running" is the time to dig into another carburetor or fuel pump and actually figure out what's wrong with the unit and fix it properly. I know I work better when I'm not under pressure.
 
tubman said:
I think the "Send it to Charlie" sentiment comes from the fact that by the time a guy gets his problem to the stage he posts it here, it's at the "wits' end" stage. A lot of the time, It's a good idea to get the car "up and running" properly before frustration sets in. Once the cars "up and running" is the time to dig into another carburetor or fuel pump and actually figure out what's wrong with the unit and fix it properly. I know I work better when I'm not under pressure.
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I need pressure.😆 Lucky for me I have a charging problem to deal with after this. Anyway i was hoping someone would chime in about removing the two one way valves. I have an idea but waiting to see if someone offers a better one. My impression is that the original OEM pumps had a screw in bracket that held them in place but later replacement pumps had the press in ones. Be nice to find one of those for ease of rebuilding.
 
Not sure where you live and what type of gas you use, but it would be a good idea to get a n ethanol resistant diaphragm. I believe Charlie's are this type.
 
If either valve is faulty, your pump will not work properly. Get a correct kit, with ethanol resistant diaphragm, and it'll be good for another generation
 
Pulled out the pressed in valves by lacing 10 stands of 28 gauge wire through the valves. After twisting the wire together I wrapped it around the handle of a big crescent wrench and wacked it with a hammer. Individualy the wire had only a 5 lb breaking strength so using 10 strands proved strong enough.
 

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Steve51 said:
Pulled out the pressed in valves by lacing 10 stands of 28 gauge wire through the valves. After twisting the wire together I wrapped it around the handle of a big crescent wrench and wacked it with a hammer. Individualy the wire had only a 5 lb breaking strength so using 10 strands proved strong enough.
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hueyhoolihan said:
i'm in the process of doing a partial rebuild of my 1941 flathead fuel pump and while doing a bit of research, i ran across this video, among others. it may or may not be of help. and although my partial rebuild will hopefully not involve the valves and their removal and installation, this video does address it.

https://www.youtube.com/watch?v=WWbcc1teqEQ&t=97s
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That would not work with the valves in my pump. If you look closely my valves had a crossmember across the opening so you could not thread a bolt into it but it gave me something to lace the wires around. The inlet valve has the spring side facing you so you have to somehow rip that out to be able to get a bolt in. It just depends on the structure of the valves as to which technique works. It took me 15 minutes. I like the wire better on the inlet side as you just have to lace it through. The outlet will depend on if you have anything to lace the wire around.
 
My other idea was to drill a small hole at the top of the two towers over the valves and punch them out with a small rod. Tap the holes for a bolt and thread sealant. Easy for future use. Or just seal up the hole with JB Weld, easy to drill out for the next time..
 
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