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1919 K45 Buick - No suction from the vacuum tank

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I got a rebuilt vaccum tank installed on the Buick this weekend. I got the car started, but in order to do so I had to prime the new vaccum tank. Once all the gas was used in the vaccum tank, it died. It doesn't appear to be sucking gas from the sediment bulb as it is suppose to. I also checked the carb and noticed the float was stuck. I fixed that and once that was resolved, gas quit running out of it. However, I am not sure where the new problem lies. Once all the gas is used that I pour into the vaccum tank, the car dies. Does anyone have any ideas? This is on a 1919 k45 buick. Could the problem be in the manifold? Does someone know of a troubleshooting technique(s)?

I appreciate the help,


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Some things to check:

* Are you getting good vacuum at the tank?

* Are the tank and fuel lines clean and open?

* are any filter screens in the system clean and open?

With my Pierce I found a vacuum leak at the windshield wiper connection plus a crudded up tank from the car sitting. With those problems fixed the vacuum system works fine.

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In my travels I have worked on a Buick K20 Roadster for the Old Rhinebeck Aero Drome that is used on most weekend in the air show. Similar problem as yours. It turned out that the fuel line was broken loose from the connector where it went into the gas tank causing a vacuum leak. I resoldered the connection and it has been working fine for the last two seasons. smile.gif Dandy Dave!

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To test for leaks in your fuel lines, use a thin piece of rubber (innertube) to seal the gas cap. Then use a bicycle pump connected to the top of the vacuum tank. Close the gas shut off valve at the bottom of the tank and slightly pressurize the fuel system with no more than 5 psi. You should quickly locate the leak by carefully listenening for escaping air.

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Here is what I would do.

When you fill the vacuum tank, use permatex on the 2 copper washers on the plug wher the gas goes into the tank. There may be a screen in the top of the tank at that location.

If the filler plug has a 1/8 pipe plug in it, you can fill it there without removing the big plug.

On any fitting screwed into the top of the vacuum tank, do not use teflon tape. It is a lubricant and it will allow you to tighten the fittings so tight before you feel the pressure that you can crack the top of the tank.

With gas in the tank and the engine running, put a small light weight piece of paper, like newspaper up to the vent pipe and see if it will be held there by the engine vacuum. You may have to increase the speed of the engine above idle to check this. This will indicate a vacuum problem, though you could have a fule line problem as well.

If there is no vacuum, remove the vacuum line from the tank and put a vacuum gauge on it or use the paper test again.

That will tell you if the vacuum problem is in the valve system of the vacuum tank or the vacuum line from the manifold.

It will most likely be the vacuum tank.

To check the valves, you need to remove the tank top. I put a piece of rubber hose on the pipe from the vent on the top of the tank and blow or suck on it while I move the float up and down to see if the valve is working. Move that fitting to the vacuum inlet and move the float arm up and down to see if that valve is sealing.

With the float up, the vent should be open and the vacuum valve closed. Float down the oposite.

To fix the valves, you need to unsolder the cone shaped piece on the valve stem to remove the arm which actuates the valve.

I used grey polishing compund which is used to polish brass made into a past with kerosene for a laping compound. I did not remove the valve from the top of the tank. I put compound in the valve and seat and with a lightweight small electric drill, I rotated the valves with the compond and lapped them in. Do not let the drill hang down with the full weight of the drill pulling the valve down.

You can check the valves with the rubber hose setup before you re assemble the actuating arm.

When you re assemble the tank, use permatex #2 on the top gasket and the 2 copper washers on the gase line plug.

If you have a gas line problem, check the plug that holds the gas line in the gas tank. There may be a screen on it. Do this before you blow air through the gas line. If there is crud on the screen, you want it out, not blown back in the tank.


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Dandy Dave,

I have not had a chance to work on the car since I posted the original question. I plan on working on it this weekend. It is starting to get very cold here! I will post a reply once I have tried getting it going again. I appreciate all the replies I have gotten from you guys.


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