Leaking Fuel Pump

[Matthew]

Last year, the fuel pump on my '56 developed a leak. Usually, it would drip at start up for about 5 minutes or so and then stop (dripping) and there was no problem. Closer inspection when it was leaking revealed that the leak was between the pulsator chamber and the main body of the pump. The pulsator chamber is a disc-like structure just above the sediment bowl, where the fuel line from the gas tank attaches. It has a neoprene 'seal' which apparently absorbs shock or 'pulsations' when the pump...'pumps'. The pulsator chamber attaches to the main body of the pump via a single, fine thread bolt with a lock washer. On my original pump (last summer's) I tried to tighten this bolt, but it appeared that the threads in the body of the pump were stripped :eek:
I hate leaks (especially with combustible fluids), so I replaced it. (You know the drill...take it out, mail back the core, wait for new pump.) I installed the new pump, and I was up and running. By the way, I didn't attempt to snug up the bolt on the pulsator chamber for fear of stripping it. It worked fine until this past weekend, when I developed ANOTHER leak in the same location!!!:mad:
Upon inspection of this pump, I found the same thing...the threads holding
the pulsator to the main body of the pump were stripped, and I couldn't tighten the pulsator to the main body. Have any of you experienced this problem?? I'm getting a bit tired of buying fuel pumps, the down time, etc.
Thanks
Matthew

[Barry Wolk]

Use a Helicoil thread insert. On final assembly use an inch-pound torque wrench to snug the bolt.

Which screw are you speaking of?

http://i244.photobucket.com/albums/gg18/barry2952/1%20Mark%20II%20docs/Vacuumpump.jpg

[Matthew]

Thanks Barry.
The screw I'm talking about is #354659-S.
In the picture, the 'pulsator' is part number 9372.
Matthew

[Barry Wolk]

From what I see a Helicoil would work perfectly. You would drill out the hole to a predetermined size relative to the original threaded hole. The Helicoil kit comes with a non-standard size tap that will cut threads for the new insert. Install the insert with the supplied tool and screw in your bolt. I would try to obtain a new bolt as the threads on the old one may be worn, contributing to the problem.

[Matthew]

Barry-
I had the fuel pump off and did the 'Helicoil' procedure on the weekend...NO LEAKS NOW!!!
Thanks for the heads up. I have no idea why this fix didn't occur to me. I guess that speaks volumes to the value of this forum. Thanks again.

[Barry Wolk]

My pleasure, believe me. I find my interaction with this site very rewarding.

[Don Keller]

I'm going to piggy-back on this old post because I have a fuel pump related question that doesn't rate a new thread. I filled the tank and replaced the inline filter as the engine wasn't getting gas to the carbeurator. I also cleaned the fuel pump sein and bowl. Presently, the gas bowl on the fuel pump has no gasoline in it after turning over the engine. Is this indicative of a clogged fuel line or a bad fuel pump? I ask this because history tells me that if I disconnect one or the other and that isn't the problem, it will be a problem by the time I get it back together.

Thanks.
Don

[Barry Wolk]

It sounds like a fuel pump, but a leak in the inlet side would cause it to suck air and not fluid. You might try filling the bowl to prime the pump.

If you blow air back through the pipe does it bubble in the tank?

The pick-up screen in the tank can be clogged, too.

[Pat Marshall]

If you disconnect the fuel supply line from the pump and let the fuel line hang down it will be below the fuel tank and gasoline should flow out of the hose. If it flows -> mechanical or line problem after the connection, if it doesn't -> fuel supply flow problem before the connection.

[Shelly Harris]

Don:

Did you replacce the samll internal fuel filter element that sits in the fuel pump above the bowl, or do you have an inline fuel filter spliced in the gas line before the pump ? I ask because when I originally opened the bowl on mine I discovered no filter element at all and instead of replacing with a stock one I just spliced in a Fram filter ahead of the pump. From your post I'm thinking that you might have a small stock one at the top of the bowl which is so dirty that you're not getting fuel flow.

[Don Keller]

Shelly, Pat and Barry,
Thanks to you all for your suggestions and questions. The only filter in the fuel pump bowl is a flat, donut shaped screen. There was some debree and about 1/3 of the bowl was full of gas upon first disconnecting it. I cleaned it all and put it back on. I had already replaced the inline filter up by the carb, it was dry. It confuses me because it seemed to be running fine when I shut it off. Barry - I don't know if I have enough force to make the tank bubble, but I'll try. It was annoying to find that you can't take the rubber hose off the fuel pump (both ends are stationary), but have to go back to metal line. I will give these things a try.

Anyway, thanks again, I was just trying to determine if the fuel pump pulled the gas from the pump bowl to the engine or from the tank through the pump bowl to the carb. I guess it's the latter, but I thought that perhaps gravity would keep the bowl filled. Live and learn or just get dumber!

As a follow-up to my headlight rim question: Whatever is holding them in there has a good grip. I think I'll just live with the slot at the top unless I have to get to the headlight. I think something may be missing in them also as I can see daylight between the rings and the chrome around the glass. Surely there was something there to keep the water out?

Don

[Don Keller]

Fuel pump update with questions asked that might benefit others. I tried the recommendations concerning my sudden loss of fuel with the following results: 1). I can hear bubbles by blowing through the line with considerable force. 2). Letting the rubber line to the fuel pump on the gas tank side hang does allow fuel to run out into my face. 3.) I primed the fuel pump basket, but still cannot get gas pulled up to the inline filter or carb when trying to start the engine.

If you reference the fuel pump diagram posted earlier in this feed (from the service manual), there are two internal filters pictured: #9365 & #9486. My Carter doesn't have #9365, but has only a screen. I'm guessing someone removed it, possibly because it has an inline filter added which I've replaced. Is this appropriate? As to the square filter #9486, could it be the culprit?

I'm leading up to the big question as to whether you all would suggest my taking the pump apart according to directions and try repairing with a fuel pump kit if needed or at least cleaning #9486; or buying a rebuilt fuel pump from Jack? I'm no mechanic, but I'm of average or better skill and can follow directions. I'd rather use the money for shiney parts!

Thanks for the help.
Don
C56R3838

[Shelly Harris]

I don't think this will be directly helpful but I mention it so you have a clear understanding about the fuel pump. The unit also funtions as a vacumn booster for the wipers. Are you experiencing bad vacuum loss at the wipers when you accelerate? If so, consider that in your rebuilding the unit or buying a rebuilt from Jack. I would think that the rebuild kit must include the necessary diaphrams for the gas and vacuum.

[Don Keller]

Shelly,
The wiper motor (vacuum) has been previously disconnected, so I don't know. That is a good point, however. Another guy in this area gets gasket material from a gasket shop in town and rebuilds his own antique fuel pumps by cutting new gaskets, etc. I might well get in over my head though and you mentioned one potential obstacle.
Thanks.
Don

[Barry Wolk]

There is probably a hole in the diaphragm. If you look at the exploded view of the pump you can see that it's a fairly simple device. I would certainly make the attempt. Worst case you can ship the parts to one of us and we'll put it together for you.

The rebuild kit will have gaskets.

[Rick Payton]

I have a problem with my car that I was going to install and electric fuel pump to correct. If the car sets overnight you have to pump the gas pedal it seems like 50 times almost to get it started. after it is first started the next time you go to start it fires right up. I know the gas must be leaking out of the bowl or being sucked back into the tank.... Any ideas other than running new gas lines the whole way back?

[Barry Wolk]

The t-pot is famous for emptying itself in short order.

The first problem is evaporation as the bowl is vented to atmosphere.

As the fuel evaporated it lowers the float, opening the needle valve and opening the valve that's suppose to keep fuel out of the bowl when it's under pressure, to make sure it doesn't overfill.

I would think that a simple check valve in the fuel line near the carb would prevent fuel from exiting the bowl, even if the fuel level drops.

Also, pumping the gas doesn't do any good in this case as it just moves the power piston in an empty cylinder.

[Doc]

Barry is correct; the problem is inherent in the older cars with the "teapot" carb that allows gas to evaporate. Many, like ours, had a dealer installed electric booster pump that can be used to prime the carb before trying to start the car--it was done long before there was such a thing as "recalls," but my sense is that the problem was widely acknowledged and dealers installed the pumps as a routine matter. When my car sits for long periods, I turn the key, run the pump for 3-4 seconds, and then start the car as you would normally (i.e. pump the pedal once, turn the key, the car starts immediately). However, looking at the VIN for Rick's car suggests he might have the "57" carb--in which case the problem may be something else entirely.

[Barry Wolk]

A simple check valve solves the problem permanently, regardless of the carb or fuel pump. It can be installed under the air cleaner and be completely hidden.

[Chuck Lutz]

Does anyone know where to buy the simple little gaskets in the fuel pump? At least one of mine is leaking and Jack only sells the rebuild kit. They have to be pretty basic, I would think.
The mechanic working on the car said both but I'm not sure the #9370 part in the picture is a gasket like #9364

Anyone have a similar problem?

[Pat Marshall]

9417 (Fuel Pump to Block Gasket) is FEL-PRO Part # 6579. 9364 (Fuel Pump Bowl Gasket) is FEL-PRO Part # 773. You should be able to get them through NAPA or most any auto parts store.

[Chuck Lutz]

Thanks Pat. I'll give that a shot.

[Mad Scientist]

If you can't find them.
The 9364 is just an ordinary gasket, how about just buying some ordinary gasket material and an x-acto knife a make your own by using the original as a template? I believe the 9370 is a one way valve to make the gas flow in the correct direct. But if you can find a similar material at your friendly auto parts store I don’t see why you could not make one of them also. It would take some time but it shouldn’t be that difficult.

[Joseph Stebbins]

I am getting ready to do complete rebuild on the Fuel/Vacuum Pump for my car. If anyone is interested I can post pictures of the process for those who have never done it.

[Barry Wolk]

That will make an excellent tutorial, thanks!

[Shelly Harris]

I am getting ready to do complete rebuild on the Fuel/Vacuum Pump for my car. If anyone is interested I can post pictures of the process for those who have never done it.

I have started a new thread for Joseph's Fuel Pump Rebuild tutorial...

http://www.markiiforum.com/showthread.php?t=3755