Cleaning 1934 Hydrostatic Fuel Gauge Glass

[JimG]

Does anyone have a recommendation on how to clean the hydrostatic Fuel gauge glass for a 1934 Ford? I have read some threads that say to use hydrochloric acid? I assume this is on a bench after you take the gauge out of the car. I understand the top of the gauge is open to atmosphere. If you take the gauge out, can you access the top of the glass to clean it using a Q tip or similar or are we talking about putting something down the connection where the brass tube to the tank connects? My gauge is out of indicating fluid and I would like to try to get it working. Photos of front and back of gauge are enclosed. Tank connection to the top of the gauge looks like it might be cross threaded to me. Thread connections on the Barn seem to recommend red gauge fluid from Macs.

Thanks,

JimG

[roadster36]

I have had luck using a product called CLR on the end of a Q-Tip.You have to remove most of the cotton from the Q-tip to get it to fit in the hole.Mine all cleaned up with that so I have no experience with pool acid.
Your line nut is cross threaded.These gauges are very touchy and there needs to be a perfect seal for them to work correctly. New nuts and ferrules are available your are damaged.
I have not found anyone that supplies red gauge fluid that will not turn clear after a while. I have tried three different vendors who all say theirs won't change colors. If you car isn't exposed to sunlight much it will take longer. The fluid color in my roadster and cabriolet changed in a few months.
-Dennis

[deuce lover]

Remove gauge from dash.Some have a brass cap at top of case.You can get to it that way by popping off that cap.If not you must remove the bezel and face.If so be careful when you bend the tabs and do only one side.Then the bezel and face can slip off.They (tabs) can break easily. Carefully pull at the top of the glass tube just a bit so you can get to the opening.I use a thin wire (Ace Hdwe)and make a hook at the end.I then roll it around a bit of kleenex.I have used acetone,lacquer thinner and brake clean.They all worked.Pour what ever you are using in the glass tube(with an eyedropper).Slide the wire contraption up and down in the tube .It might take several times to get it clean.Then pour the solution in the back hex brass and clean that.Make sure that the copper rod in there is removed.Fill from the back with that cleaning solution.It should appear in the glass.If not that small copper line from the brass hex to bottom of glass is plugged.If fluid appears then blow it out and let dry.Gauge is ready to be installed(put copper rod back in).On the threads - you might have to take a small file and clean them up since you can't get a die on it.Make sure that nut threads on and off easily before installing gauge.Hope this helps.

[stangblue]

I agree with deuce lover, I had a long conversation with a vendor at Hershey this past week who makes gauges for antique cars, He recommended a pipe cleaner with stiff bristles that is used with lacquer thinner. Going in and out of the tube several times to free the stain, ring whatever. Also he sells the red fluid that everyone I have talked too and others that recommend (Packards ect. whatever) that it is stated above not to do the things everyone complains about. The vendor I have bought the red fluid is Classic & Exotic Service, Inc. Web site: www.classicandexotic.com . Ending on this note, I wonder if you could keep the top of the gauge housing sealed with the little brass plug found on original gauges or something else that would seal the opening such as ie, duct seal, tape would help alleviate the evaporation and stain of the fluid residue? Thoughts? I'm adding a direct link in the cataloge for the fluid http://www.classicandexotic.com/stor...red-fluid.aspx

[JimG]

I have finally taken my hydrostatic fuel gauge apart and cleaned it all up. The inside of the steel part of the gauge was somewhat rusty, so I soaked the gauge in Rust 911 for a week. Came out looking pretty good. I painted the inside with a small brush and some rustoleum. I cleaned the glass tube with a Q tip - just pull off most of the cotton and leave a little bit on. It worked great. The copper tube seems clear and I rinsed it well with water that I squirted through it and let it dry. Put everything back together last night and it looks good as new. One of the studs holding the gauge on to the dash bracket broke off when I was removing it. I drilled it out and am going to try using a screw to hold it in.

I bought red gauge fluid from Classic and Exotic. Now I'm ready to reassemble. My question is - how much red liquid to put into the gauge? When I first started investigating this, I picked up the enclosed pages on the Barn. These seem to indicate that you should set the red liquid level to minimum in the gauge and that it will adjust itself as you drive the car. My gas tank is currently full, not empty. Does anyone have experience on where to set the liquid level to start with when reassembling a hydrostatic fuel gauge?

[DavidG]

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I second the advice regarding the use of a pipe cleaner for the glass portion and a fine wire (telephone wire in my case) for copper tube portion. I've not tried CLR, but metal prep (phosphoric acid) does the job as well.

[JimG]

Any thoughts on where to put the red fluid level to start? Here is another publication I found. Seems to indicate it should be at the minimum level.