michealbernal

1928 standard vacuum fuel system diagnosis

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In bought a rebuild kit for my vacuum fuel system and installed it.  I cleaned all the rust out of the tank and put it back together but it doesn't seem to be working.  It is getting vacuum.  This seems like a pretty simple system.  How does one go about diagnosing what might be wrong with it?  Any info appreciated.  

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I rebuilt mine and while I don’t have it installed back I the car yet, that will be this weekend 🤞🏼, but after talking to “Hal” at the Preservative Society who was most helpful and beyond a pleasure to talk with, he guided me to some do’s and don’ts on what to look out for with these SW Vacuum Fuel Pumps!!

 

Hal instructed me to  take the inner tank and while holding the flap shut momentarily on the bottom of the inner tank submerge it into a bucket of water or a deep Rubbermaid container just shy of the top of the inter tank and watch to see how much if any water seeps past the flap when you let go of the drain flapper, Hal said just a little seepage is ok but no more than  a tiny bit!

 

Then also drain the inner tank of water and then while holding the inner tank down into the water the same way in part one above, tank your mouth and chin and create a seal between the inner tank and your mouth/chin and while still holding the inner tank down into the water suck in with your mouth and see if it creates a vacuum when sucking in with your mouth, no water should come in at all when you are sucking!! 

 

Did you you try anything like this!?

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Posted (edited)

I have not thought a lot about how to test the vacuum tank once assembled.  I did put together a rebuild procedure if this helps you.  I took some notes from William and added them at the end.    Hugh

  266568945_vacuumtank1.thumb.JPG.4053942413b162eb9f4f28ef395676ba.JPG844747434_vacuumtank2.thumb.JPG.987b8689fd67ecbf1d5ac9850d9d9b74.JPG1774972798_vacuumtank3.thumb.JPG.a443caf3a044421a9087cd37e14dc0fd.JPG689435927_vacuumtank4.thumb.JPG.341355bb1e6e1fed00e77294733c5f59.JPG996431923_vacuumtank5.thumb.JPG.63d327f487425cdffe00b385d4671c6c.JPG

Edited by Hubert_25-25 (see edit history)
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Good procedure Hugh.  I have also used gas tank sealer on the underside of the pot metal lid to seal any cracks or porosity.

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Posted (edited)
On March 14, 2019 at 10:25 AM, Mark Shaw said:

Good procedure Hugh.  I have also used gas tank sealer on the underside of the pot metal lid to seal any cracks or porosity.

 

I used KBS Coatings Gold Standard Fuel Tank Liner to line both the inner and outer and keep corrosion to a min, i kept it away from where the inner tank meets the outer tank so no sealing issues and everything seems to work fine with reassembly.  I didn't line the middle of the inner tank where the float goes into the bushing guide of the inner tank.  

Edited by Crazyfamily (see edit history)

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On my '25 Buick the problem was with the big brass nut that holds the fuel outlet line on the top of the fuel tank.It seemed tight,but I installed a new gasket and the problem was solved.It was sucking air.

 

Jim

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Hubert 25-25 and crazyfamily.  Thank you so much for the diagnosis info.  I would have never figured that out without your help.  The bakealite valve on the bottom of the inner tank has a small chip out of one lower corner.  I think that is at least part of the problem.  

Does anyone make a replacement for that valve or is there something that can be substituted?  Thanks again for all the assistance.  Mike

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40 minutes ago, michealbernal said:

Hubert 25-25 and crazyfamily.  Thank you so much for the diagnosis info.  I would have never figured that out without your help.  The bakealite valve on the bottom of the inner tank has a small chip out of one lower corner.  I think that is at least part of the problem.  

Does anyone make a replacement for that valve or is there something that can be substituted?  Thanks again for all the assistance.  Mike

 

Tell Hal I sent you, he recently helped me with my rebuild kit and all I can do is spread the word!  He took about 5-6 phone calls from me and always called me back when he got back in!!

image.jpg

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Www.classicpreservation.com

 

the kit above doesn’t have the flapper in it, but it’s avail separately from him!

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Hal is one of the good guys, he helped me with my Cadillac vacuume fuel pump.

I highly recommend his products and service.

Jim

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Mark and William, 

     Thanks for the notes.  I added them into the procedure.     Hugh

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