1929 White vacuum tank

[WPVT]

I just started the truck up for the first time in quite a while. The first step is always to prime the vacuum pump, which I did, and the engine started right up. The difference this time is that the vacuum tank didn't refill on its own. I primed it again with about a quart of fuel, with the same result. The tank is in very nice shape and it was rebuilt a little while ago, so the only problem is that it has been sitting idle. Is there something I can do short of opening it up ? Letting it sit for a week filled with fuel ? Giving it a hammer tap ?

Secondly, it has a small mesh filter at the inlet that occasionally collects small particles. I removed the fitting and checked that out to see if that was the problem. It wasn't, but I am wondering if that is an original filter or someone's add-on. It's a nuisance location for a fllter since it requires removing  and then replacing an elbow with a pipe thread.  I've thought of eliminating that and installing a sediment bowl between the gas tank and the vacuum pump, but their isn't enough room between the pump and the firewall. Is there usually a filter preceding the vacuum pump ?

[old car fan]

The mesh filter  is original to the tank.

[oldford]

You might be losing vacuum where the rubber line comes in. Sometimes they get hard and, if so, there wont be enough suction to draw the new gas into the tank. Try replacing the line with a new one.

 

Frank

[WPVT]

I seem to recall that when you manually fill the vacuum tank with fuel, that at some point there should be a "click" where a float causes a spring loaded valve to close. That would be an indication that the innards of the tank are working. Am I remembering correctly ? 

[edinmass]

Looks like wipers are hooked to the tank....bad idea.........should have a line direct to the manifold. Just search Stewart Warner vacuum tanks here, there are a bunch of threads on how to troubleshoot, repair, and have diagrams and parts availability. My 17 White sate for 80 years, and the tank worked fine with no adjustments. All I did was install a new gasket. They work great, and are 100 percent reliable. 

[Stude Light]

To help diagnose issues, I install a vacuum gauge in the fill hole. This way you can see if the tank is getting a vacuum and you can watch the cycle.

 

No vacuum - look for a clog or break in the vacuum line to the engine

Weak vacuum - look for a leak or bad seal

Vacuum but no fuel - look for an issue on the line to the tank

Cycle intermittent - float or valves in the fuel pump

[WPVT]

58 minutes ago, edinmass said:

Looks like wipers are hooked to the tank....bad idea.........should have a line direct to the manifold. Just search Stewart Warner vacuum tanks here, there are a bunch of threads on how to troubleshoot, repair, and have diagrams and parts availability. My 17 White sate for 80 years, and the tank worked fine with no adjustments. All I did was install a new gasket. They work great, and are 100 percent reliable. 

Thanks Ed. The first thing I did when I bought the truck was to disconnect and remove an electric fuel pump and get the vacuum tank functioning again. That involved changing jets on the carb to accomodate the significant pressure difference between the pump and gravity. Eventually I got it right.

 

If I disconnect the wiper hose from the vacuum tank, and connect it to the manifold instead, I'd probably do it at the same fitting on the manifold that the vacuum tank uses. So would I be accomplishing anything ?

[John Bloom]

1 hour ago, WPVT said:

I seem to recall that when you manually fill the vacuum tank with fuel, that at some point there should be a "click" where a float causes a spring loaded valve to close. That would be an indication that the innards of the tank are working. Am I remembering correctly ? 

Yes, you are correct. You can hear it click when the float rises. 
 

Edited May 15, 2023 by John Bloom (see edit history)

[edinmass]

If vacuum volume or pressure drops, you may starve the tank and cause a low/no fuel issue. Since the tank only pulls once every two minutes or so.....it could cause a running problem that is hard to diagnose.  Basicly going direct to manifold gives a much better volume/reserve to the wipers, and keeps the fuel delivery system out of any troubles. Obviously wipers on a 29 truck are seldom if ever used.......but a vacuum leak in the tube, pipe, or wiper motor could also be a problem in the future. Best, Ed

Edited May 15, 2023 by edinmass (see edit history)

[stakeside]

5 hours ago, WPVT said:

I just started the truck up for the first time in quite a while. The first step is always to prime the vacuum pump, which I did, and the engine started right up. The difference this time is that the vacuum tank didn't refill on its own. I primed it again with about a quart of fuel, with the same result. The tank is in very nice shape and it was rebuilt a little while ago, so the only problem is that it has been sitting idle. Is there something I can do short of opening it up ? Letting it sit for a week filled with fuel ? Giving it a hammer tap ?

Secondly, it has a small mesh filter at the inlet that occasionally collects small particles. I removed the fitting and checked that out to see if that was the problem. It wasn't, but I am wondering if that is an original filter or someone's add-on. It's a nuisance location for a fllter since it requires removing  and then replacing an elbow with a pipe thread.  I've thought of eliminating that and installing a sediment bowl between the gas tank and the vacuum pump, but their isn't enough room between the pump and the firewall. Is there usually a filter preceding the vacuum pump ?

Is this an original tank for this vehicle? I found that these tanks were sized for there application. Here is a list of tanks. There should be a stamped number on the tank. 

[WPVT]

2 hours ago, edinmass said:

If vacuum volume or pressure drops, you may starve the tank and cause a low/no fuel issue. Since the tank only pulls once every two minutes or so.....it could cause a running problem that is hard to diagnose.  Basicly going direct to manifold gives a much better volume/reserve to the wipers, and keeps the fuel delivery system out of any troubles. Obviously wipers on a 29 truck are seldom if ever used.......but a vacuum leak in the tube, pipe, or wiper motor could also be a problem in the future. Best, Ed

Got it. Thanks again Ed.

[WPVT]

5 minutes ago, stakeside said:

Is this an original tank for this vehicle? I found that these tanks were sized for there application. Here is a list of tanks. There should be a stamped number on the tank. 

I'm quite sure it's original. The truck was never used all that much and everything is pretty much as it was delivered, with the exception of the carburetor. 

[old car fan]

I will look it up tomorrow, certain  that is the correct  tank .and many had the fitting  for the wiper. Vacuum  is vacuum. It doesn't  take  much  to run.If you split  at the manifold, say at 8,compared  to vacuum  tank, still 8.Still split,no vacuum  made, it is what is is.

Edited May 15, 2023 by old car fan (see edit history)

[edinmass]

Volume is not the same at the manifold vs the tank……….

[WPVT]

1 minute ago, edinmass said:

Volume is not the same at the manifold vs the tank……….

So analogous to a compressed air tank....a 50 gallon tank with 100psi or a 5 gallon tank with 100psi ?