Need 6V gas tank sending unit rebuilt

[dono50]

Any information on reliable source to rebuild my 50 Ford gas tank sending unit would be appreciated.

[rotorwrench]

You might try some of the instrument shops. If they can repair the King Seeley indicators then the sender should be near the same construction. If you pop the cap off the to of the sender, you can see the bi-metallic strip and the little contact points set. They have a calibration resistance spool in there too. Sometimes they just need the little points cleaned up.

[19Fordy]

The K/S units insides look like this 1940 unit.
If you find a rebuilder please let us all know.

[jake197000]

i sent an original 38 packard sending unit in to get rebuilt by so called experts a fewyears ago.what i got back was a cheap generic sender cobbled onto the original holder didnt work for s..t b careful and ask first.

[koates]

Originally Posted by dono50

Any information on reliable source to rebuild my 50 Ford gas tank sending unit would be appreciated.

.
Hi there, May I ask why you think it requires rebuilding or more accurately to be repaired or tested. Have you tested the sender unit or the dash gauge and wiring ? You can lever the top off the sender unit carefully and inspect the contact points at the end of the bi-metal strip . Clean them carefully without bending anything with a fine strip of doubled over wet and dry paper. Also inspect the fine coil winding to see if it has been overheated or burnt. If it is all burnt then the unit is more than likely is unrepairable. On no account make alterations to the gear wheel adjustment. Check the contact point under the cover is clean. Make sure the sender unit and fuel tank has a good ground to the chassis. Regards, Kevin.

[dono50]

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I will try to get mine working.Thanks for the advise,now I know what to look for.

[G.M.]

Most old Ford fuel senders I worked on have a resistance of 0 to 74 ohms.
Use an ohmmeter from the body of the sender to the terminal screw. It
should move in the range above as you move the float up and down. G.M.

[edhd58]

The one i bought from Bob Drake said it worked 6
6 or 12 volt. May look into a nude one to see

[rotorwrench]

King Seeley won't work well off resistance alone. They work off current and pressure. Current for the heating element and pressure against the bi-metallic strip. The amount of pressure on the bi-metallic strip is reproduced in the indicator unit with pressure against the indicator needle.

If you replace the sending unit with a rheostat type unit, you have to change the instrument to that type as well to get full accuracy throughout the range of meter movement.

[JSeery]

Originally Posted by G.M.

Most old Ford fuel senders I worked on have a resistance of 0 to 74 ohms.
Use an ohmmeter from the body of the sender to the terminal screw. It
should move in the range above as you move the float up and down. G.M.

How do you measure resistance on a points system?

[G.M.]

Originally Posted by JSeery

How do you measure resistance on a points system?

What points???? G.M.

[JSeery]

The points in the sender. Current is regulated in the sender by opening and closing a set of points (contacts). The rate at which they are opening and closing determines the current in the system between the sender and the gauge. The float position changes the tension on the point and thus the rate they vibrate. If the points are open the resistance will be zero and if closed, a very low value based on the coil (windings around the bimetal strips). There should be no change in the resistance once the points close regardless of the float position. The attached operation description is related to Mercury/Lincoln units, but they all functional work the same.

[koates]

GM, You are thinking of the later type sender unit (late 1950s on) which is a variable resistance or rheostat type. The senders used from 1936 to the 1950s are the type made by King Seeley and have contacts and a heated bi-metal strip inside and work in a chopping on/off switching system as described by JSeery and rotorwrench in the previous posts. Regards, Kevin.

[G.M.]

The sender in my 36 gives an ohms reading of about 17 ohms which is about
3/4's of a tank. I have a loose sender that reads from 0 to 24 ohms. I have a
loose sender that also measures 0 to 24 ohms. When clipped with jumper wires
to my gauge the gauge go's from empty full. Never had the sender out of the
tank, it's a roadster and not that easy for me to get at. G.M.

[JSeery]

Must be a replacement unit that uses resistance.

[FireEngineMike]

I made the same mistake of buying a sending unit from Mac's and discovering that it does not work well. The problem turned out to be a rusted out float in the original unit. It looks just like the pictures that 19 Fordy posted. I also got resistance readings of around 10 to 74 ohms from it. I would like to clean up or have the unit professionally cleaned up and calibrated before I drop the tank and reinstall it. I jumpered it to the gauge wire and grounded it and the fuel gauge read 7/8 full with the float all the way up and empty with the float all the way down. Morris Gauge had been recommended at one time but their website is defunct. Any thoughts?

[40 Deluxe]

Originally Posted by JSeery

The points in the sender. Current is regulated in the sender by opening and closing a set of points (contacts). The rate at which they are opening and closing determines the current in the system between the sender and the gauge. The float position changes the tension on the point and thus the rate they vibrate. If the points are open the resistance will be zero and if closed, a very low value based on the coil (windings around the bimetal strips). There should be no change in the resistance once the points close regardless of the float position. The attached operation description is related to Mercury/Lincoln units, but they all functional work the same.

It just hit me: What you're describing is Pulse Width Modulation, used on late model vehicles to control transmission pressure, EGR and much more. It's supposed to the latest and greatest thing to get precise control. And here Ford had it in the 1930's! Just not electronic.

[JSeery]

Originally Posted by FireEngineMike

I also got resistance readings of around 10 to 74 ohms from it.

That is the reading for a replacement resistance sender unit.

Ford up to 1986 - 73-10 Ohms
Ford 1987 & up - 16-158 Ohms
GM up to 1964 - 0-30 Ohms
GM 1965-1997 - 0-90 Ohms
GM 1998 & up - 40-250 Ohms
Mopar up to 1986 - 73-10 Ohms
AMC 1950-1977 - 73-10 Ohms
Autometer -240-33 Ohmswww.jalopyjournal.netis the most common however other ohm ranges are made
Classic Instruments - 240-33 Ohmswww.jalopyjournal.net(excluding vehicle specific gaugewww.jalopyjournal.netkits which use factory ohm range)
Dolphin - 0-90 Ohms
Dakota Digital - Programmable to work with most Ohm range senders
VDO - 10-180 Ohms

King-Seegley work with points, they are either open or closed. In the closed position you would see some ohms reading for the heater coil.

[FireEngineMike]

I'm sorry JSeery - do you ever get tired of having to repeat yourself? Obviously the PO replaced my sending unit. So the seller is wrong if a for sale supposed OEM/NOS sending unit shows a range of resistance (as above) between the connection and ground. How do you tell if a sending unit is OEM/NOS and works? I just looked at the Detroit Iron reprint of the shop manual and it says to connect a new sending unit and operate the float arm. If the gauge works then the old sending unit was bad. Tough to do online or at a swap meet.

[JSeery]

I hear ya. I've never seen a Ford or King Seegley test procedure except pull and replace. The first thing I would try to check would be to see if you can get the contacts (points) to open and close by moving the float arm on a fuel gauge and checking with an ohms meter. Closed should read very low ohms and open is open, LOL. They are very well made gauges and can often be brought back to life by cleaning the contacts.