Wiring the beasts.....

[Bob Carriere]

So many pit falls I decided to start a new thread.....may be it can become a section of its own.

Frustrated today......

spent the morning taping all the rear lights with the old fashion tar electrical tape..... tested the light and one brake light is not working...... remove all the tape and found that the original metal connectors on the 1940 pigtail is not quite the match for modern bayonnette type and can easily not engage fully and slip out...... solution cut off and replace the original male connector with a 2016 connector.... so confident that it is now working I retaped all the connectors with plastic tape but before covering all the plastic tape with the old style tar cotton tape.... I tested the system and the same light is not working..... now about to trace the cross over wires to the pass. side......

One more frustration..... got some original switches....NOS.... still wrapped sealed in cosmolene....... they have a very heavy bloom of white oxidation and one was actually rusted...... maybe it rained in Oshawa the day the box was sealed..... so I opted for after market switches with the little ball at the end similar to the originals..... but the orientaton of the off/on tab means the switches are showing off when in the one position....... solution from Grant..... take the switches apart carefully rotate half of the assembly 180 degrees re=assembled and now they work..... by the way those are the Princess Auto switches...... I prefer them to the originals as they have screws to hold the eyelet connectors.... the original have tiny little jewelry screws that were corroded.

Now back to the barn.....

Cheers

[Hanno Spoelstra]

Good subject, Bob!

I have been solving some problems with the 70-75 year old wiring recently. The old steel wire is getting oxidized, switches are making bad contact, so there's a loss of voltage from battery to light, coil etc. I had only 4.7 Volts at the coil. After cleaning up contacts it went up to 5.7, still a loss of 0.3 volts.

I am now convinced I have to replace the wiring with new wire and switches....

Lets use this thread to share experiences.

Hanno

[Private_collector]

In Australia, Vintage Wiring Harness do a nice set of replacement wiring for several versions of CMP. Looks original, but modern reliability. Cost = around $600-650AUD. At least it was when I bought mine a couple of years ago.

http://vinwire.com.au

In my case, I need to reduce length of wiring running aft, to accomodate shortened chassis length, but that won't be hard....I hope. Back then, they had limited CMP options, but now have harnesses for cab 12 and F15A as well. Worth a look.

[Bob Carriere]

Finally resolve the faulty brake light..... found another original 1940 male fitting that had slipped out during tapingof the wires.

Now all the ligths work. After cutting out the old male connector and replacing with a modern one I retaped everything in plastic tape then covered the whoel set up with original tar covered cotton tape. Amazing the amount of time spent on details.

I was lucky to be working with a repro wiring harness made by Phil W. he used the exact color codeing used on the Original loom and it makes it easier to identify and follow the wires.

Some while ago I purchased an original cab 13 front wiring harness....does all the front to the middle where the rear section connects.It is old NOS but really too brittle to use...... it was nice to unfold it and check it's fit agaisnt Grant can 13 to see how it snakes in place.

I am temporarily running Halogen sealed beams but in the future I will make a set of headlights buckets with the proper separate lens/reflector set up with the inside marker light.

word of caution..... on a cab 11 and cab 12 headlight bucket the depth of the bucket nbarely accommodate a sealed beam due to the large connector at the back of the sealed beam...... I tried and old burned out bulb and had mor clearance..... so if you order onlinemake sure you measure and make sure it fits.
My solution was to buy another 3 prong connector that had the wires coming out at 90 degrees at the back and gained sufficient room.

Getting the headlight wiring inside the front fender bracket and into the small hole in the cast upright bracket of the grill is a real trick. Grant used a long bare steel wire inserted front the engine side and fished out back to the hole under the headlight....slow but do-able.

Having an extra 12 volt battery, even a poor one with a low charge, is priceless to check lights and continuity WITHOUT have to reconnect the trucks own battery.

Save you legs if working on an early design..... have a ready avaialble step stool that allows you to get up to pumper height and lean into the engine compartment...... and you will be going up and down many times so if necessary made on,,,, and sturdy.

One of my quest.... to find the original 3 wire plug that fitted in the female socket of the cab 11/12 design..... I have one but the remaining 4 inches of wires are grimped permanently....... would love to ear from others on what they have, found or plan to use. No repro available to my knowledge...

Off to the barn

[Hanno Spoelstra]

Originally Posted by Private_collector

Worth a look.

Thanks for the tip, Tony!