1933 Fuel Gauge Problem

[Doug 845]

I just got done (I thought) on installing a rebuilt gauge I bought from Baxter Ford and it looks great. I removed the fuel tank and cleaned it along with the sending unit. I installed new fuel & air lines as well. I added the red fluid to the gauge as instructed to the empty line. I added fuel and it registered correctly as 3/4 full. The next day the gauge fluid level dropped so I added more red fluid. I thought that temperature might be a factor since it dropped 45 degrees. Now the temperature is about 50 degrees hotter and the gauge is past the full mark. Does temperature effect the red gauge fluid? If not, what could be the problem?

[G.M.]

I don't think temperature would have a noticeable effect on the readings if it is the correct fluid. If it drops much in less than 2 days I would look for an air leak at the line connections. G.M.

[Doug 845]

The strange thing is that the red gauge fluid level actually has risen since I parked the Ford in the garage a couple weeks ago. It is now above the full mark. I bought the air line repair kit from a reputable dealer in the Northeast and followed the installation instructions. If the gauge fluid level rises anymore, I'll have to remove some fluid. Any suggestions on what I should do?

[deuce_roadster]

Some people put silicone sealer around the nuts after tightening them at each end of the air line. My 34 would sometimes after sitting overnight not read quite what it did before but after driving a little would read correctly as gas sloshed around in the tank.
IF you didn't solder up all the tiny cracks in the "cups" that catch fluid it is possible that the tank unit is at fault and not just an air leak. Like GM said though check that first. Oh, one more thing, did you solder the tapered sleeve at the tank end of the air line after slipping the nut on? Not all the lines come soldered and it needs to be soldered to the small line or it will leak air there.

[B-O-B]

Doug 85
You should have a length of rod(probably brass) in the hex reservoir used for adjusting the fluid level. You might want to try a different length of rod.You can do a search( box at the top red line) for more info.

[Doug 845]

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Deuce - I did solder the tapered sleeve nuts at both ends of the line. I did not see any cracks in the cups of the sending unit when I thoroughly cleaned it. I'll apply silicon around the nuts to see if that helps.
B-O-B - I didn't realize that the gauge has a rod in the hex reservoir. How do I adjust it? The instructions only said to insert a toothpick into it to take some fluid out if I overfilled it.

[B-O-B]

Go here; THE RED line at the top & type in hydrostatic fuel gauge adjustment
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[FlatheadTed]

You added fuel and it read correct ,then it dropped (air leak ) you then add fluid (to full ) . Find the air leak and lower the fluid .use a cotton bud .Ted1

[morrisgauge]

This instruction sheet may be of some use.

[fourfords]

I have a stock '33 with a professionally restored hydro static fuel gauge. My experience is that they are a bit squirrely. That's why Ford changed to the electric type.
The gauge requires you drive the car with all the bumps and turns so the gauge attains equilibrium as it works with the ambient air pressure somehow. I use the trip meter and fill up every hundred miles. Even with the best restoration, do not rely on the gauge's accuracy. Happy motoring and good luck!

[fourfords]

Forgot to mention that if you do not drive your car for a few of days, the red indicator fluid drops down. When you drive the car around for a while, the indicator fluid rises to its proper level. It is possible you do not have an air leak at all, just not enough time to get used to the nature of this gauge. These gauges do not operate like any other "Normal" gas gauges. Just my experience. Hope its helpful.

[BIG MIKE]

Air leak? G.M. knows his stuff Id go with that opinion .

[Doug 845]

Thank you all for your replies. I was very careful when I installed the gauge to make sure I did it right the first time. Despite my attempt I somehow missed something. The car hasn't been started in two weeks but somehow the gauge fluid has risen after I parked it. I see the instruction sheet that Morrisgauge kindly provided and noticed that it pertains to a 1935 gauge. Did the '33 / '34 gauge also have the removable calibration rod? I didn't notice one when I installed it. I will siphon out some fuel to see if the level drops in the gauge and then drive it around a little to see how the gauge responds.

[morrisgauge]

The style of gauge is the same, that instruction sheet was from a particular repair manual that didn't include all models. The theory is universal to the hydrostatic fuel gauges and some didn't come with calibration rods, those are to compensate for differences in tube volume, etc.

www.morrisgauge.com

[FlatheadTed]

Ford wasn't the only one who used this type of gage ,Packard ,Auburn and many others ,I have one for 20 years with no fluid drops or discoloration and maybe one top up ,Ted

Originally Posted by fourfords

I have a stock '33 with a professionally restored hydro static fuel gauge. My experience is that they are a bit squirrely. That's why Ford changed to the electric type.
The gauge requires you drive the car with all the bumps and turns so the gauge attains equilibrium as it works with the ambient air pressure somehow. I use the trip meter and fill up every hundred miles. Even with the best restoration, do not rely on the gauge's accuracy. Happy motoring and good luck!

[fourfords]

Originally Posted by FlatheadTed

Ford wasn't the only one who used this type of gage ,Packard ,Auburn and many others ,I have one for 20 years with no fluid drops or discoloration and maybe one top up ,Ted

That is correct about other manufacturers.

Your experience is different than mine. I would have liked to have had your experience with these gauges instead. My system holds a test vacuum. Having said that, Do you have some practical tips on how to achieve your results? I'd like to improve the accuracy of my instruments too.

Thanks in advance-

[Doug 845]

I siphoned out 5 gallons of fuel and removed some of the gauge fluid (from the top of the tube). I then drove the car around a little and to my amazement the fluid actually rose again past the full line. Can someone please explain this? I am totally perplexed.

[Terry,OH]

Drain the entire gas tank nearly dry and then calibrate the gauge to exactly Zero. Don't add any more fluid to the gauge after calibration! Then add the fuel back to the tank. You don't have to drive the car the gauge should read correctly. If the level drops to an improper level there is a air leak. Often at the sender where the fitting attach to the short lines going into the tank they crack at the back of the fitting. Look closely with a magnifying glass and re-solder if they are cracked. When you replace the hydrostatic line solder the end fittings on with the line all the way into the fitting.

[Pat/Ohio]

Doug...I would say you have way too much red fluid installed. I would remove more of the fluid until the gauge reads closer to the amount of gas you have in the tank. Then drive again. Good luck, Pat

[FlatheadTed]

Four fords ,All of the above and, As well as removing or adding fluid ,The unit may need to be tuned to the sender by shorting or lengthening the brass rod if you have the original one that came with it then it should be ok .It works on displacement,you can use a brass small brazing rod ,For discolour tion I clean them out with Hydrochloric acid soldering fluid, Ted

Originally Posted by fourfords

That is correct about other manufacturers.

Your experience is different than mine. I would have liked to have had your experience with these gauges instead. My system holds a test vacuum. Having said that, Do you have some practical tips on how to achieve your results? I'd like to improve the accuracy of my instruments too.

Thanks in advance-