204E Fuel Sender Units

EnFo p/n: 204E-9275A/B/C

For:    '59-67 Anglia 105E sedan
          '61-64 Consul Capri / Classic
          '56-62 Zodiac / Zephyr / Consul sedan.

Unit Manufactures / Type:   Float Sender Unit. Resistive wire wound Bobbin, Single Sweep.
    - Smiths T.F. 1000/23 WET   EnFo p/n: 204E-9275A
    - AC  7228816 12V D5         EnFo p/n: 204E-9275B
Replaced by 204E-9275C. I assume that T.F. means mounted on top of fuel tank-WET, submerged.
AC/Smiths units are interchangeable.

Rebuilt 204E Fuel Sender Unit

Unit Manufacture specs:    Resistive range: 12-22 Ohms to 240-290 Ohms (depending on the # of wire turns on bobbin and condition of the unit)                              
Wire type: Nichrome #34 .006 diameter. approx. 20 Ohms per foot non-magnetic.
Wire length: 14 ft. 200 turns.

Typical failures: Intermittent, corrosion, worn or damaged, and unit not grounded. Check that the unit is properly grounded to the body (there should be a ground wire from the sender unit mounting screw to the body/chassis) before removing the unit.


Removal:  Remove unit from fuel tank. Remove the access plate from the unit (two screws or two tabs) Corroded/stuck units should be soaked in a cleaning solution ( DO NOT SAND-BLAST). Discard units with excessive corrosion on the aluminum body that has worn thru. Units in decent shape with moveable parts are more desirable. Check the float for small holes or fuel inside. Repair holes with silver solder and flux, if necessary.

Corroded Unit but bobbin in good shape

Condition: Check the condition of the wire-wound resistor, sweeper contact, wire connection to the terminal. Clean the face surface of the wire-wound resistor with a cleaning solution/acid brush.

Connect a digital Ohm meter, one probe to the body of the unit the other probe to the spade connector. Move the float arm slowly from one end to the other end. A steady reading of approximately 12 ohms to approximately 290 ohms.

Corroded terminals should be removed by drilling out the rivet on the top connector side. Replace worn parts. Re-attach with a 1/8" x 5/8" long aluminum pop rivet.

Re-Winding Resistors: This procedure will require a NZ-1 winding machine. NZ-1 has been modified  to accept a bobbin. It's nearly impossible to re-wind by hand. I will show you how I accomplished this.

NZ-1 Manual Winding Setup

                               

Mounted Bobbin wound with Kanthal

Arm removal with punch and hammer

Installing arm. Place arm in vise. Tap on sweeper stud.

Remove the arm/float assembly as shown (mark the position of the arm).
Remove the sweeper assembly (detach the braided copper ground strap, if there)
The bobbin is safety crimped in its guide. Carefully remove the safety tabs. Cut the wire to the terminal. Carefully remove the bobbin. You may have to move it back and forth until loose. Use WD-40 if needed. Remove the resistive wire. It may come off in sections. Total length 14'.

Alternative Resistive Wire:   Kanthal A1 #34 gauge (.006 diameter ) 21.1 ohms per foot. Magnetic.
Kanthal resistive wire: chromium, aluminum, Iron.

Nichrome and Kanthal cannot be soldered with a typical soldering iron, unless excessive heat was applied. So, wrap the end of the wire a couple of times around the interior terminal. Apply electrical solder to the terminal covering the wrapped wire completely with solder.

                             
Result:  165 turns on the bobbin and installed in the unit came to 22 ohms to 242 ohms.
I sprayed some EL601 Red Insulating Varnish on the coil but the fuel washed it off. So leaving the wire bare did not effect the resistive range. Also, I didn't attach a braided copper wire from the sweeper rod to casing ground as i figure that the cover plate notch should press against the top sweeper rod for grounding. Some units had the ground strap missing or broken in that case the unit still worked properly.