The ballast resistor is on the circuit breaker assembly. The resistance changes some when it heats up (more) so just check to see that it has resistance to find out if it's any good. Or look for a NOS one like I did because I didn't trust mine.

 

Wow, nice truck! Ditto on the brakes! Those guys should correct any problems, no charge. I've never seen anyone start with this good of a vehicle. Great job!

 

I've seen it in person. I is indeed a very nice example of a jailbar tonner. Just hoping the Cap'n will toss his old wiring harness across the water to Orcas Island because it still looks better than the crumbling cloth covered harness I'm running in my tonner panel. (hint). Like Sarah Paylin and the Russians, I can 'almost' see his town from my kitchen window.....

 

Thanks for the kind words, Lumbah. I wouldn't have the courage to do what many of you folks tackle! GB - once I get the wires out of the truck, consider them yours. Do you want me to tag the ends as I take them out? I ordered a batch of connectors today, and as soon as they get here, I'll start in on the work. I don't know what I'm looking forward to most...seeing if the rewire solves the starting issues, or seeing the restored cluster in its proper place.

 

Thanks Cap'n. Sure, any tagging will be helpful. I dragged home a '46 tonner that used to be a pickup and I'm going to go back that way with it. It isn't that great and I'm thinking it may live out it's useful life as my junkyard dog around the place. The jailbar woody I'm now involved in may get all new 'storebought' wiring, but with all the worn out jailbars showing up around here, your old wiring will live on in something for sure....

 

I've been making some progress with the rewiring, after a couple false starts (turned out I'd initially ordered the wrong headlight socket harnesses). One thing I'm struggling with is figuring out how to connect the cowl harness to the temperature sending unit and oil sending unit. The harness has bullet connections on the wires that lead to those, but it's not clear how those should connect to what's coming off of each unit. As you can see in the attached photo, the oil sending unit currently has a long copper wire that looks like it's wrapped in a spring (this leads all the way to the dash gauge), and the temp sending unit is what looks like a copper tube heading from the unit to the dash gauge. Neither seems to be well suited to join to the bullet connectors of the harness (not in the photo). It would be great if I could see how others have connected their harnesses to the sending units. Thanks in advance for any words of wisdom!



Oil sending unit is in lower center, with spring-like covering over the copper wire coming from it. Temp sending unit out of view, but you can see the copper tube (?) coiled up and leading to it.

 

I could be wrong, but both are mechanical gauges; no wiring necessary. The wire wound one is likely the temperature gauge sending unit; that's the location of my 1940 temp sending unit, albeit with an adjacent water outlet.

 

That's what I initially thought it should be, but the wiring harness has a wire for each (with a butt connection at the gauge side and another on the engine side), and the harness shows that these are supposed to be for the sending units. It's not clear how those are supposed to match up with the existing sending units.

 

I'm surprised that no one with more experience has jumped in to help. My 1940 has electrical gauges in the cluster and sending units in the engine. The temp sending unit is in the driver side head. I added a mechanical temp gauge which has a wire wound tube like yours that installed into a new fitting in the passenger side head (had a plug in the threaded hole from the factory). I just went back to the beginning of your thread and noticed the 2-gauge set added under the dash. I would bet that they are mechanical temp and oil pressure gauges and both tubes go to them. Poke your head under the dash and you should see the same tubes going into them as you see in the engine compartment. The two wires in the harness are for the OEM electrical sending units for the cluster gauges. Check the other head for an electrical temperature sending unit (same location) which would have a small threaded hole in the top where you would attach the temp wire. Follow the copper tubing down the side of the block and note where it enters a fitting. Check to see if the fitting is in a tee with a sending unit on the other leg of the tee and look for a wire. The PO either installed the tee to have both oil pressure gauges or removed the OEM electrical sending unit and installed the fitting for the mechanical gauge in its place. Good luck.

 

You're absolutely right - the PO apparently replaced both of the original electrical sending units with mechanical versions. If I'm going to use my restored cluster, I guess I'll have to replace both of those units. I also ran across a post in another part of FTE (for slightly newer rigs) talking about 8BA engines having two temperature sending units (linked together). Mine does have a second original style temperature sending unit plugged into the engine on the passenger side, though it's not connected to anything. I think while I'm at it, I'll replace that one (it looks pretty old and rusty), and link the two units together as should be the case for this engine. Thanks for the helpful tip!

 

Read this thread for more info on how the dual temperature sensors work.

https://www.ford-trucks.com/forums/1...p-sensors.html

I like my setup with the original single sensor in the driver side head feeding the cluster temp gauge and the mechanical gauge sensor in the passenger side head so I have a numerical reference. I think you can install a tee in the block in place of the oil pressure sending unit and have both the cluster gauge and the mechanical gauge. If the aux voltmeter is connected correctly it gives better info with the alternator than the cluster ammeter.

 

The volt meter and the cluster ammeter are measuring two different things. The volt meter is measuring the voltage output of the alternator/generator and the ammeter is reading current flow (amps). Exactly the same, only completely different measurements.
Having both electrical and mechanical gauges works well. Especially with the low oil pressure flat heads have at idle.

 

In the interest of trying to keep the original look as much as possible, I've gotten rid of the extra set of gauges, and am going to just have the original cluster. I had it restored a while back by Cushman Speedometer, who did a bangup job with the restoration at a reasonable price. My rewiring is far enough along that today, I was able to install the restored cluster, making me feel much closer to having the truck back on the road. Made for a good Saturday!

 

Here's the cluster before the restoration.

 

The interior looks great. Cannot wait for the update telling us how well the gauges work.