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Posted By Discussion Topic: '36 fuel pump problems (pic) -- page: 1 2     Flatbob 10-25-2011 @ 9:52 AM reply profile send p.m. Member Posts: 437 Joined: Oct 2009 Sorry if this post appears twice. Had debris in the fuel system a few days ago, problem solved and car drove great but as soon as I shut it off it would not restart. Debris isn't the problem this time as line, fuel pump and carb are clean. I have a new pump a couple years old and an original earl '36 pump that both appear to be in good condition. The newer pump won't draw fuel from the tank and the original will draw to the sediment bowl but not deliver to the carb. Initially I used a one man brake bleeder to draw fuel from the tank to the inlet on the carb, having done that the car would start immediately and as I say drove great but would not restart. Any ideas? Can anyone explain the 4 (breather?) holes on the bottom of the original pump? supereal 10-25-2011 @ 10:12 AM reply profile send p.m. Senior Posts: 6819 Joined: Oct 2009 Does the car have the original fuel line from the tank to the firewall? Due to the alcohol in gas, rust and dirt have become a problem. The line is just large enough (1/4") to supply adequate fuel supply, and any accumulation of crud reduces the qualtity until the fuel pump can't draw a sufficient amount. If it takes a My-T-Vac to draw fuel, I suspect line replacement is due. Be sure the gas tank cap is properly vented. The holes on the lower side of the fuel pump are vents to allow the diaphragm to breathe as it flexes. Flatbob 10-25-2011 @ 10:50 AM reply profile send p.m. Member Posts: 437 Joined: Oct 2009 Super, I replaced the fuel line with one from Nacewizc. I've blown fuel line clear in both directions. I've been cranking with gas cap off, vent line is also clear. If I can somehow get fuel on the carb side of the pump it will run but no luck so far. Thanks, Bob Dolman 10-25-2011 @ 2:08 PM reply profile send p.m. New Member Posts: 177 Joined: Dec 2010 Had a similar problem with my '34 until I pulled the pump pushrod and found that it was severely worn. Put in a new pushrod and the problem went away. Just a thought. 37RAGTOPMAN 10-25-2011 @ 2:37 PM reply profile send p.m. Senior Posts: 1965 Joined: Oct 2009 here is a idea, what about taking one of the pumps off the stand, work it by hand and see if it pumps fuel, have someone sit in the car, with hand on the ign switch, just incase, hole the pump in you hand and pump the fuel and see if the car starts and runs, I would suggest, rebuilding the pump with a modern kit from THEN AND NOW in MASS, I use them, this way you keep the pump original and do not have to use a CHINA part on your car, this is what I like to do,one less CHINA part, one more AMERICAN has a job, hope this helps 37RAGTOPMAN supereal 10-25-2011 @ 3:10 PM reply profile send p.m. Senior Posts: 6819 Joined: Oct 2009 If the main line is clear, I'd check the flex line at the firewall. These lines have a rubber liner which can swell shut, or collapse. Flatbob 10-25-2011 @ 3:17 PM reply profile send p.m. Member Posts: 437 Joined: Oct 2009 Dolman, took your advice & pulled fue"l pump push rod but measures out right on the money 7.87" as I would expect it to as the car only has 267 miles on it. I replaced it with a new one from C&G when I rebuilt engine. Thanks for the thought. Bob Flatbob 10-25-2011 @ 3:24 PM reply profile send p.m. Member Posts: 437 Joined: Oct 2009 37ragtopman, like all your ideas especially the China part. Will contact THEN AND NOW. If I understand correctly you're suggesting I use a fuel source other than the gas tank to check fuel pump operation; such as a small cup? Is it possible to activate pump by hand fast enough to pick up fuel? Thanks Bob 37RAGTOPMAN 10-25-2011 @ 5:42 PM reply profile send p.m. Senior Posts: 1965 Joined: Oct 2009 I think, if you use a punch to work fuel pump it should be able to run the engine with no problems. leaving the fuel lines hooked up. use leather gloves. so you do not cut yourself, I enclosed a picture of the kit from,THEN and NOW, I understand they make there own parts. and you can see this kit does a few different years of fuel pumps, and the good quality of the parts ,check the picture hope this helps. 37RAGTOPMAN Lets hear how you made out, This message was edited by 37RAGTOPMAN on 10-25-11 @ 5:45 PM TomO 10-26-2011 @ 7:55 AM reply profile send p.m. Senior Posts: 7256 Joined: Oct 2009 Bob, Here is an except form my V-8 Times article on fuel pumps. Failure to prime: There have been many complaints about gas evaporating from the carburetor when the vehicle sits for more than a week. This means that the fuel pump must prime itself and pump some gas into the carburetor before the engine will start. The Ford V-8 fuel pump must be able to generate and hold vacuum in order to draw the gas from the tank and lift it as much as 18 inches to the sediment bowl. Once the pump is primed, the pump must deliver gas to the carburetor. The source of the vacuum is the diaphragm and the input valve acts to hold the vacuum. A good pump will prime itself in about 30 seconds and start the car in about 60 seconds. Add about 30 seconds of time to fill the glass sediment bowl. Do not crank your car continuously for this length of time or you will burn out the starter. If you are having a problem with priming the fuel pump, hook a vacuum gauge to the input of the fuel pump and crank the engine. The vacuum gauge reading should rise to 10 inches in 18 seconds. Stop cranking the engine and watch the needle on the gauge. It should take at least one minute to reach 0. In order of probability causes of failure in this area are top cover or sediment bowl gasket leaks, input valve not working or defective diaphragm. The valves in the new after market pumps made by Air-Tek will not hold vacuum above 5 inches. This may lead to priming failures. The valves in the pre 1941 fuel pumps are more likely to fail than the later type. If the above test showed that the fuel pump was OK, move the gauge to the next connection in the input side of the fuel pump and retest. This will check out the flex line and the connections to the tank. If these tests results show good connections, the problem could be plugged lines or tank pickup. A bad connection may not leak fuel, but it will leak vacuum. The flex lines can leak at the crimp for the connection or from pinholes caused by not being alcohol resistant. Another cause of failure to prime is rust clogging the line or the pickup in the tank. To check the line, disconnect it at both ends and blow through it from the fuel pump end with compressed air. The tank end should be directed into a container to catch whatever comes out of the line. Did you solder the ferrules to the gas line at both the tank and flex line connections? Doing this, helps to seal the line from air leaks. The 4 breather holes are just one way to allow the diaphragm to move air. The other pump breathes through the one hole. There would be little differences in the operation. The diaphragm creates vacuum and the return spring creates the pressure to push the fuel to the carburetor. The original pump may have a weak spring or defective valves. Use your vacuum gauge to check the output pressure. It should be fro 2-3 lbs. Tom

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