How To: C15a Wire-3 restoration

[Phil Waterman]

Originally Posted by Jordan Baker

Well with some barn cats ......

Phil, can you check your records for me please on the length of the rear harness? I’m looking for the length from the change over switch towards the front. Please and .....

Anyone have any pictures on where the wires from the fuel tanks are run and secured to the frame?

Hi Jordan

Having made harnesses for HUPS, C60S, C60L, C15A that the front harness seem to be the same length with the individual differences being for which Pattern and then on Pat 13s early or late instrument panel. From what I can figure/observed rear harness for, 134, and 158 inch wheel base are all the same from rear to just in front of the rear axle. That the difference is the length forward to the connection lenght to the junction point with the front harness.

If you think about it this would make a lot of sense for parts interchangeablity.

Will look tomorrow for photos and more details.

Cheers Phil

[Jordan Baker]

Grant,

Yes it’s an off the shelf item from Vintage Wiring Harness in Australia. Item number CV425. I had them add the separate wires for turn signals as well. The quality is great and I’m very happy with it. All of the leads are tagged, however the numbers don’t match up to the wiring diagram in the C15a manuals. Saying this they may have used a different wiring diagram and matched it to them. One other thing I have noticed is that you have to provide your own light sockets for the dash lights. If I come across anything else I post about it. Ignore the box as it is only being used for holding CMP goodies such as side lights and other original bits.

The stainless braiding came from https://www.cabletiesandmore.com/sta...aided-sleeving. I ordered online and it arrived by the end of the next day via UPS.

I went with stainless as the tinned copper was a lot more. The other advantage was that the stainless had a good expansion range. So using the 1/2” stainless, I was able to do all the sizes as found on the main harness.

Thanks Phil. I look forward to seeing what you’ve got in your files. I’ve got what I believe to be an original rear harness. I’ll have to slip under the truck and see how it goes then compare to the new made one. I do know the new one is way longer then needed for a 15cwt.

[Jordan Baker]

Started installing the front harness today. It was quite the job getting the dash wires to feed through the hole. Eventually everything got pushed and pulled through. I also started securing the harness to the cab frame with some clips. I’m so glad I went the extra and put the metal shielding on everything. It looks just like how the original should.

In my last photo showing the various holes. What are they all for? I know the top one is for the main wiring harness. Does anyone have any documents on what goes where?

[Grant Bowker]

The oval hole gets a rubber grommet with 4 holes in it that cushions the temperature line, choke cable, throttle cable and oil pressure line. the two smaller round holes above and below the oval are for bolts securing the tin that holds the grommet.
One vendor is Steele Rubber https://www.steelerubber.com/firewal...met-60-0010-45 Other vendors sell it too, Steele just had a clearer photo than Chevs of the 40s....

[Jordan Baker]

Thanks Grant. I should have said that I have the rubber bushing. Any idea on the other two larger holes? I’m guessing the speedometer cable goes in one of them.

[David Dunlop]

Jordan.

Would the vacuume lines for the wipers occupy one of them?

David

[Phil Waterman]

Hi Jordan

Your truck has one more hole comin in from the engine compartment than I've seen before, wonder if it was drilled to replace a wire or possibly for a replacement temperature gauge tube.

Here is same area on my HUP
Small Web 2012 HUP June 029.jpg

As you have discovered the only practical way to work on the dash and engine compartment wiring is with nose off. I make this comment to anyone planning to replace or do major work on the wiring in this area.

Jordan though I'll guess you have looked at the section on wiring on my web page, here is the link for people getting into wiring on thier CMPs http://canadianmilitarypattern.com/C...formatioSn.htm I've included the link instead of posting over all the photos because you can punch down to much higher resolution than is practical on MLU.

Cheers Phil

PS In response to Davids comment on vacuum line, the vacuum line for the wipers on mine goes up through the center post on the windshield.

[Jordan Baker]

Hi David.

As Phil says the vacuum line goes up through the top between the main windshield frame.

Phil, yes I have been checking out your photos from your website quite a bit the past few days.

[Grant Bowker]

Originally Posted by Phil Waterman

Having made harnesses for HUPS, C60S, C60L, C15A that the front harness seem to be the same length with the individual differences being for which Pattern and then on Pat 13s early or late instrument panel. From what I can figure/observed rear harness for 101, 134 and 158 inch wheel base are all the same from rear to just in front of the rear axle. That the difference is the length forward to the connection length to the junction point with the front harness.
If you think about it this would make a lot of sense for parts interchangeablity.

This morning I compared the parts books for C15A and C60L, most of the wiring harness part numbers were identical (differences for applications such as portee, arctic, instrument styles, wireless shielding, etc.).
To allow for the difference in wheelbases I would have expected either that there would be long, medium and short rear harnesses or that there would be extension harnesses to fit between common front and rear harnesses. Maybe I wasn't seeing clearly or didn't recognize what they were calling the parts but I didn't see either of these approaches described in the parts books....

[Phil Waterman]

Hi All



WARNING - BE SURE TO SECURE WIRING HARNESS

Yes, using all caps is like shouting, and regarding this warning I am, I learned the hard way. While looking for photos for this thread found the photos of the wiring harness FIRE I had in a freshly made wiring harness. The cause of the fire was simple I had not yet secured the harness with the clamps it shifted was shorted out burned out the harness. Nearly burned through a rubber gas line. I could have lost the truck, the other two trucks parked in the shop and the shop.

Pat 12 Cable Fire Sept 07 018.jpg Top to bottom, speedo cable, fuel line, main harness, and bottom battery cable.

Be sure as you go along to secure the wiring harness with cable clamps, that's what all those 1/4 holes are for. Also watch very carefully your routing in the area around the brake master cylinder, starter, speedometer cable and fuel line.


What happened was I was in a hurry to test the truck and hooked every thing up and drove it around quite a bit great fun. Figured I'd get around to putting in all the clamps. What happened was the speedometer cable shifted shorted out to the brake light switch on the master cylinder. That heated up and melted the insulation on the main power going to the starter that that lit up the speedo cable which was tight with the main wiring harness running forward to come up to the dash. Resultant damage was a foot of the main harness had to be cut out and replaced.

All because I didn't take the time to put clamps on everything before powering the system up.



Now back to Jordan's excellent restoration thread with a question. What are you going to use as overload protection?


Cheers Phil

[Jordan Baker]

Warning acknowledged.

I’m slowly working away at installing the harness. So far I’ve used 5 clips just for the wires either side of the engine.

Overload protection? Would this be the current limiting device that is mounted to the backside of the dash?

[Phil Waterman]

Originally Posted by Jordan Baker

Warning acknowledged......


Overload protection? Would this be the current limiting device that is mounted to the backside of the dash?

Hi Jordan

Yes, that's the current limiting device I'm speaking of. Of the three of these on my trucks only one actually worked to limit the current. It vibrated to beat the band to limit current at 30-40 amps when bench tested. The other two would pass 40 amps with not a sound.

The first the one on the HUP I used, the other two I did not use, instead putting a modern thermo braker in, forget if I used 30 or 40 amp units. Now as I think about it think going back and adding a 30-35 amp fusible link at the point where the main harness picks up power at the starter might be a good idea. Now that your work as reminded me I should go back and add it to all three of my trucks.

Other thread over the years have discussed the value of adding a battery disconnect switch. I used a marine battery switch on my C60S when I installed the 261 engine. It let's me run truck on 6 volt normal conditions, then if for any reason the truck doesn't start I can switch just the starter over to 12 volts. In either position the trucks normal electric system only gets 6 volts. The switch as an off possition as well. The 12 volt battery normally just drives the water pump for the shower, lights in the shower/toilet and the modern radios in the cab.

Cheers Phil

[Jordan Baker]

The harness still isn’t fully installed yet. I’ve been busy working on some side projects the past week or so. However I did manage to get the following parts all finished and installed on the truck these past few days. The radiator shroud turned out looking great. I made up some wooden forms for the dished part. My first attempt didn’t go well but my second was bang on. I even spot welded just like the originals. I did have a minor fit issue with the bottom of the shroud and the lower radiator outlet.

[Jordan Baker]

Once I cut out a minor section the shroud went on just fine. I also made up a felt strip for the top shroud to seal against the bottom of the top tank. I used stainless safety wire for the felt staples. Now the radiator is all done and ready to go on.