Hydrostatic fuel gauge innaccurate
 

Just finished rebuilding fuel system on my 34 and the NOS fuel gauge registers accurate empty but will only go to just above 1/2 when full. I added another calibration rod to the gauge and this made no difference and there is not room for another calibration rod. Also used indicator fluid from two different vendors still no difference will only read just above 1/2 when tank is full. Anybody run into this before?

Robert

Re: Hydrostatic fuel gauge innaccurate
 

The sender in the tank has two cups and a pair of small tubes, one for each cup. It would appear the upper cup is blocked or it's tube. You can use liquid toiler bowl cleaner on the brass it can get into the small tubes, flush (pun intended) it out with lots of water, do not get the cleaner in your eyes or on your skin.

Re: Hydrostatic fuel gauge innaccurate
 

The liquid in my '34 hydrostatic fuel gauge dried up years ago, and there appears to be sediment in the capillary. Any suggestions what to use to clean it out?
JohnI

Re: Hydrostatic fuel gauge innaccurate
 

you will need a repair kit from Macs

Re: Hydrostatic fuel gauge innaccurate
 

Removed tank sending unit and could not find any problems with it. Replaced with a different overhauled tank unit anyway. Same thing reads a little over 1/2 tank when tank is full. Fuel level stays level and does not fluctuate or drop off with time. Could it be the vapor pressure of the gas?
Robert

Re: Hydrostatic fuel gauge innaccurate
 

When the gauge reads empty it should have two gallons in it .at that point you should just see the red liquid appearing

Re: Hydrostatic fuel gauge innaccurate
 

Trouble with the repair kit from Mac's is the red fluid turns clear in a couple of years.

Re: Hydrostatic fuel gauge innaccurate
 

Has anybody tried the red fluid from Classic & Exotic apparently it is a higher grade of fluid than Macs but its a lot dearer to.

Re: Hydrostatic fuel gauge innaccurate
 

I believe the calibrating rods act similar to a brick in the toilet water closet. They calibrate the amount of liquid in the tube. If so and you add calibrating rods ,that are not necessary, it is possible for the gauge to run out of stored fluid below the full mark and burp some of the air pushing the red liquid up the glass column. If this happens the gauge would loose calibration and never read "Full" . I would remove any extra calibrating rods in the hex tank (go with one or none as you found it). check calibration on an empty gas tank and add gauge liquid to the 0 line, then fill the tank and see if you have proper reading.

Re: Hydrostatic fuel gauge innaccurate
 

What a great resource Fordbarn is! After 3 years of trying to get my hydrostatic gauge to work correctly I found this post.

To date I have
1. Cleaned and repaired the gauge head
2. Cleaned and repaired the sender unit
3. Replaced the Airline
4. Replaced the fluid with Macs Fluid
5. Replaced the fading Macs Fluid with Classic and Exotic Fluid
6. Replaced the Fading Classic and Exotic Fluid with Original 1934 Factory
NOS fluid
7. Replaced the (Bob Drake) Fuel tank with a Bob Drake tank with the fuel
sender mounting plate from an original tank welded into it to eliminate
the adaptor plate you need to use with the Drake tank for the original
sender
8. Tried about 500 different sizes of brass rod to try and calibrate the gauge

However despite my obvious OCD efforts I could never get the gauge to read over 3/4 full even when the tank was full to the brim.

Read the post above today and removed the calibration rod and the gauge reads perfectly full when full. I need to use the search button more !

Karl

Re: Hydrostatic fuel gauge innaccurate
 

Hi,


My 32 gauge is giving me trouble too and noticed this article. Can someone post a picture of the calibration rod please? I don't know what you're referring to. My gauge and tank unit is as attached with no mention of calibration rods.


Thanks


fhttp://www.fordgarage.com/pages/32fuelgauge.htm

Re: Hydrostatic fuel gauge innaccurate
 

Your pictured 1940 convertible does not have a Hydrostatic system.

Re: Hydrostatic fuel gauge innaccurate
 

I also have a 32.

Re: Hydrostatic fuel gauge innaccurate
 

And a nice one at that!!

Re: Hydrostatic fuel gauge innaccurate
 

Thanks!

Re: Hydrostatic fuel gauge innaccurate
 

I redid my hydrostatic fuel gauge last year. No new parts - just reused what was there. I took it all apart. The steel enclosure for the gauge was a little rusty near the top of the glass tube, so I soaked it rust 911 for a week and then thoroughly cleaned and dried it and then painted it with rustoleum. I cleaned the glass tube with a Q Tip with most of the cotton pulled off. I also painted the little piece of cardboard that was inside the gauge white, as it was pretty yellowed from age and also stained with red liquid. I used red gauge fluid from classic and exotic. Some people on the barn said to put the red liquid up to the lowest level on the gauge. I used a syringe to put the liquid in after I installed the gauge. This allowed me to remove some liquid after I overfilled it by accident - hard to put the liquid in under the dash and see the level at the same time. I ended up with the level at about the 1/4 mark. I figured this was good as I have read that the liquid does evaporate over time. I cleaned up the end of copper tube good and soaked it in CLR overnight. I them attached the copper tube to the gauge using Teflon tape on the threads. The gauge never goes all the way to full. It tops out at about 3/4 to 5/8. I have learned to just live with it that way. Others I have communicated with on the barn have the same situation. I am satisfied with it.

Re: Hydrostatic fuel gauge innaccurate
 

JimG- I expect the reason your gauge is not going to the top is probably due to the tiny tube from gauge to tank. It is next to impossible to clean it and usually needs to be replaced and blown clear with a hand pump not with compressor or by mouth. This tube is so small that the smallest amount of moisture or dirt will affect accuracy. Also in order for the gauge to be completely accurate the car must be sitting level. The reason Henry kept using the Hydrostatic gauge is probably the same as why he used cloth insert tops and mechanical brakes. Who knows?

Re: Hydrostatic fuel gauge innaccurate
 

I've heard the same thing from many of my vintage friends - "it's an old car " "Just accept it " I have one of my friends who enjoys rattles and squeaks in his car as it shows him it is vintage

I think we tend to assume that as our vehicles are old they have inherent faults which we should just accept . In actual fact I would wager heavily that when Ma and Pa Kettle forked out their hard earned depression cash to buy a new Ford V8 in 1934 they would have expected an accurate fuel gauge . I am also sure that if they found that it never read over 3/4 full they would have returned it to the dealer for repair or replacement (as we would with a new car today). The fact that Ford sent dealers regular information about how to correct faults such squeaks etc confirms that 1930's buyers were just as picky as us today when it came to their new cars

My approach is if it worked correctly when new there is no reason why it can't be made to work correctly now. How hard you try and how much you spend before you give up is determined by your obsessiveness

Karl

Re: Hydrostatic fuel gauge innaccurate
 

Very good point Karl.

Re: Hydrostatic fuel gauge innaccurate
 

I have rebuilt several (>10) 32,33 gas gauges to sell at swap meets and have had them all work fine.
On all of them, I clean them first with lacquer thinner sitting in them for about a week. I then use a piece of .o23 wire from my MIG gun and carefully poke it down from the glass tube side. I have found that most of the clogs are at or very close to the attachment to the glass tube. As stated above, a Q-tip with the cotton removed will fit inside the glass tube and clean it well.
If I can blow air from the brass inlet side (use a syringe, not your compressor when liquid is in the glass tube) and see bubbles in the lacquer thinner, I know that the small brass or copper tube is clear. (I am doing all this with the gauge disassembled and the metering rod intact. Next while holding the gauge in 1 had, I tap the open end of the brass inlet tube with a finger rapidly and see if the liquid (lacquer thinner ) rises in the glass tube. IF it does, I make it go up maybe 1/2 inch and hold my finger tight over the inlet. If the liquid remains at that level and doesn't creep down, I know there are no leaks. All testing and cleaning of the glass tube done with lacquer thinner.
I am VERY fortunate to have a bottle of Ford Script Gauge fluid that is still as red as it was 80+ years ago. The bottle is about 1 1/2" in diameter and 6" high and about 3/4 full. Enough for quite a few gauges.
My first gauge I restored was for my 32 5w worked perfect on my bench. I put it in the car and the red fluid that was on zero disappeared! I took it back out and on my bench it was back at zero. I took a gauge that measures angle and found what angle my dash was at with the car sitting on my level garage floor. Next I held the gauge at that angle and the red fluid disappeared! I put a piece of sheetmetal in my vice and bent it to the angle of the dash in the car, clamped the gauge to it and put drops of the red fluid in it until it read ZERO. Reinstalled it in the car and it has been accurate ever since. I did clean up the tank unit, solder up any cracks in the edges of the chambers that collect air, and install a new air line before I rebuilt the gauge.

SO if your car is on a rake, it will effect your gauge and you need to know the angle of the dash before you zero the gauge with fluid. You can see this if you pay attention to the gauge after you put liquid in it and tip it a little. Anyway that is my 2 cents.

Some gauges where the small tube between the glass and brass fill tube is crushed or clogged and is plugged permanently can be repaired by soldering a segment of good tube in but I have never messed with that, I haven't found that many gauges that I couldn't open up.