1956 Fuel Pump Stopped Working

My fuel pump seems to have stopped working. While driving, we went over a bump and the brass reducer/adapter that attaches to the output fuel line from the pumps cracked. It banged against the frame/cross member (looks like on new pumps, the outlet has been offset by 90 degrees to fix this issue)

I replaced the adapter, hooked everything back up and it would not pump fuel. Pulled the fuel pump out and took it completely apart (pain in the rear end to put the internals back together) and when I actuated the arm, I can hear "sucking" noises, but when it's installed, no fuel pumps. Not sure where to go from here and want to do a little trouble shooting before I buy a new pump.

Thanks
 
Sorry...1956. When I reinstalled the pump arm, I tilted it down to make sure it went under the lobe. The arm has a "shiny" spot on top of the arm where I could tell the lobe and arm has been in contact. I found a thread that talked about installing. It recommended taking a picture in the engine to see where the lobe is. I took the picture and can see the lobe. I am pretty certain the arm is under the lobe. Also, my vacuum wipers work while I am cranking the car...so it seems the lobe is actuating the arm. thanks.
 

biddle

Forum Moderator
Staff member
Please include the model year in the subject as prompted. I added it for you.
model-year-TBF.jpg
 

jack-in-sac

Well-Known Member
My fuel pump seems to have stopped working. While driving, we went over a bump and the brass reducer/adapter that attaches to the output fuel line from the pumps cracked. It banged against the frame/cross member (looks like on new pumps, the outlet has been offset by 90 degrees to fix this issue)

I replaced the adapter, hooked everything back up and it would not pump fuel. Pulled the fuel pump out and took it completely apart (pain in the rear end to put the internals back together) and when I actuated the arm, I can hear "sucking" noises, but when it's installed, no fuel pumps. Not sure where to go from here and want to do a little trouble shooting before I buy a new pump.

Thanks
Like the old TV repairman would always ask; Is it plugged in? Are you getting fuel to the pump? How old is the hose from frame to pump? Ther was at one time a spate of hoses from offshore that easily collapsed and/or deteriorated from the inside resulting in fuel not passing through the hose. I would think if the vacuum wipers work then the pump is likely working. Modern gas can deteriorate old rubber fuel lines causing fuel starvation. On other thing, have yo tried starting the car priming the carburetor to help the pump fill due to the engine running.
 
the fuel has to travel much father than VACUUM. you can prime it all day long but it might not pump one ounce of fuel. The pump has two sides, Vacuum and pressure, fluid is heavier than air. gas=7 lb per gallon+- / air not much.
good luck
 
Jack in Sac, Richfords,

Thank you for the suggestions. I pulled off the hose going into the fuel pump. It looks good. Does not seem to collapse and is intact..no deterioration, cracks, etc. Hooked the fuel line going into the pump back up and cranked the car a couple times for 10-15 seconds. Left the discharge fuel line off of the pump ...no gas.

I hooked up a hand pump to the fueling from the tank, just in case it is empty (gauge says 1/4 tank). Pumped fuel out of the line with no problem.

Disassembled the fuel side of the pump one more time just to make sure the internals are hooked up. Both diaphragms on both sides (fuel and vacuum) are moving.

Really at a loss. There is a "seasoned" (did not want to say old) mechanic in town that has done some work for me in the past. I am going to call him, see what he has to say. thanks for the help.
 
First of all, never test a fuel pump by loosening the fuel line to see if fuel comes out while cranking the engine. Instead disconnect the fuel line from the carburetor and connect a fuel pressure gauge directly to the disconnected line. The fuel pump pressure specification is 4.0 to 5.0 psi at 900 rpm.

When you disassembled the fuel pump did you check the fuel pump valve assemblies? If one these valves stick open, the fuel pump will not pump any fuel.

(see attached pictures)

doug7740
1955 Thunderbird Blue
100_6333.JPG 100_6334.JPG
 
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If you pumped fuel through the line with no problem.
I know you want to fix it yourself i get that, but I think it's time to call it and get a new pump.
Breaking down somewhere isn't worth it.
Good luck, Tom
 
First of all, never test a fuel pump by loosening the fuel line to see if fuel comes out while cranking the engine. Instead disconnect the fuel line from the carburetor and connect a fuel pressure gauge directly to the disconnected line. The fuel pump pressure specification is 4.0 to 5.0 psi at 900 rpm.

When you disassembled the fuel pump did you check the fuel pump valve assemblies? If one these valves stick open, the fuel pump will not pump any fuel.

(see attached pictures)

doug7740
1955 Thunderbird Blue
View attachment 12129 View attachment 12130
Doug,
Thanks for the method for checking the fuel pressure. It looks like a safer approach.

I did check the valve assemblies (I was calling them check valves...now I know the correct name). I inspected them for debris that may be holding them open, but did not see anything. I also gave them a little poke with my screw driver and they appeared to move freely.

Thanks
bruce
 
If you pumped fuel through the line with no problem.
I know you want to fix it yourself i get that, but I think it's time to call it and get a new pump.
Breaking down somewhere isn't worth it.
Good luck, Tom
Tom,

As a matter of fact, I have ordered a new pump...and you are right, there is the pride thing of fixing myself....but after pulling the pump out about five times and double checking everything....I am just about ready to wave the white flag.

I think this pump may be pretty old. The inlet and outlet are very close to each other...not like the pictures above that show them about 90 degrees apart.

thanks
bruce
 
As an update, got a recommendation that adding fuel to the carburetor to run the engine and help pull fuel thru the line. (which was also recommended in this thread) Tried this a couple times, with no luck. Also tried pulling the hose to the pump inlet off the fuel line from the tank and poured fuel into the line to fill the fuel pump. Turned the car over, but this did not help with priming the pump. A new pump arrived yesterday, so I'll be swapping that out in the next couple days.
 
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Final Post, Problem fixed: Embarrassed to say the fuel input and output lines on the new pump were attached backward. The old fuel pump inlet was at 5 o'clock (looking from the top of the pump), whereas the outlet on the new fuel pump was at 5 o'clock. The outlet on the old pump was at 6 o'clock where as the inlet on the new fuel pump was at 9 o'clock. The good news is neither the inlet or outlet fittings sit on the frame/cross member, like it did with the old pump, so the fitting won't snap off when I hit a pump. Thanks to everyone for the suggestions.
 

CSPIDY

Well-Known Member
Thanks for the update, seams like this may be a common problem with replacement pumps. I had a simulator problem on a 57 Farlane. Uses the same pump as the Tbird
 
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