VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 '32 Sending Unit

I'm thinking of dropping the gas tank this fall after driving season. When I got the car, the gas gauge worked, but not accurately. Now, whenever I turn on the key, the needle goes to full and stays there no matter how much gas I have. I know replacement sending units are available, but I would rather repair what I have if that's feasible. I also know that somewhere out there is a thread on this which I can't find via the search feature. If the problem turns out to be mechanical in the float and linkage, should be pretty straightforward. More likely, it's electrical. In which case, how do I proceed?

Hi goffe,

Sounds like you have either a broken connection from the sending unit to the gauge, or a bad ground at the sending unit, or both.


Here are some links from the Electical-6 Volt forum:

https://vccachat.org/ubbthreads.php/topics/234790/1

https://vccachat.org/ubbthreads.php/topics/229583/1

https://vccachat.org/ubbthreads.php...auge/Search/true/Re_Fuel_guage#Post46004

Happy Motoring,

Dan

I have found the replacements unsatisfactory for 1931-2 gas tanks. You can purchase resistance wire from Radio Shack (sorry don't have the part number handy). With it you can rewind the coil part of the sending unit. The total resistance of the coil should be ~ 30 ohms. If the wiper is corroded cleaning it may be all you need to do. You may also find that the float cork is deteriorated or saturated. There should be an article in the G&D soon that tells how to replace the cork with a brass float.

I have recently discovered model A Ford modern fuel resistant plastic floats that fit straight on to 1931 Chevrolet sender units and they are almost the same dimensions and have a hole through the centre and they are less than $4 each. I have also fitted them to a 1930 sender and all you have to do is anneal the wire where it fits into the original cork and they slide straight on.Have a look here.http://www.snydersantiqueauto.com/uploads/A9313C-9407-xl.jpg

Thanks chevy6 ,
Try this link.

http://www.snydersantiqueauto.com/2450

I should have mentioned that after you anneal the wire that the cork floats fit on in the 1930 sender you have to straighten the wire and put in a couple of bends in the wire in the appropriate places to hold the float in place.

Without annealing the wire it will likely break when attempting to bend it. I know from experience.

I know bringing up an old thread is bad form, but here goes. I just got around to dropping the tank to take a look at the sending unit. It came out easily. The corks looked very dubious and will be replaced. When I got the car, the gauge worked ok, but this season, it stayed at full once the key was turned and stayed that way no matter how low the gas got. When I got the unit out, it was free and mechanically worked easily. The cover is riveted on and I haven't opened it yet. Resistance through the unit is 0 ohms whether the float is up or down. Any thoughts before I go further? From reading the cited posts it seems that a 0 ohm reading should show empty on the gauge, not full. ???

Sounds like the resistance wire is probably broken.

Here's what I found when I opened up the sending unit. The operating rod from the float ends in a right angle bend with a contact point held against the rheostat by a thin spring. The contact point was bright and there was electrical continuity through that part of the system. I concluded that that part of the unit was ok. The top cover has the semi circular rheostat lying against but insulated from it. One end is riveted to the case and the other terminates in an electrical connection for the gauge wire, also insulated. Somewhere this insulation has broken down and the rheostat is shorted to the case. Does it make any sense to even try a repair? Has anyone done it who can shed some light on this?

John Wolf & Company repairs sending units.

http://www.johnwolfco.com/

Hello goffe,
I did not locate John Wolf Co. when I clicked on the link. A Google search [fuel tank sending unit repairs] suggested www.tristarradiator.com. Give it a look and check out the [Services] offered.

Thanks everyone. I think I'm going to fool with it myself and see if I can solve the short. In the meantime, if someone has a new unit, I would like to know about it.

I used the replacement unit from the Filling Station and it seems to work fine. Pt# RV-63 . I have the old one (apart) which you can have if you want to continue trying to repair the original. I found it easier for the $25.00 or so to just install the universal one the FS sells. I don't believe there is any noticeable difference once installed.

Apparently John Wolf changed his web site address. Here is the current link to his web site:

http://www.antiqueinstrument.com/

I had a similar problem with my '30 unit. I found the rivet that was supposed to ground the end of the resistance wire to the case was rusted to a point that it no longer provided a ground. There was continuity from the reaistance wire to the rivet but not from the rivet to the case. I simply cleaned the rivet head and the case and put a drop of solder on it and everything worked OK. I also used Snyder Antique plastic floats wich seem to be more reliable than the cork ones available.
Hope this helps.

ArtM