No question this time, just a solution for the broken wires and cracked insulation on 31-year old sensor wires.

While cleaning the water pump housing, one of the leads to the thermo switch broke right at the top of red epoxy. The other one was missing the wire insulation at the same location.

My solution, as the part is no longer available, was to attempt a fix. I was able grind away enough of the red epoxy and with an X-Acto knife scrape off enough of the previous hidden wire insulation, to expose the wire. A drop of solder and then solder the wire lead.

For insulation and added strength, I applied 500 degree epoxy to the repaired and other unbroken lead.

I also used the same epoxy on other connections where the wire was still connected but the insulation broken.

The outer insulation on the lead to the oil level meter was broken and two layers of shrink-wrap should seal it and add some strength.

(Giving a tiny little back for all the help I've received.)

 

Nice work!

 

Thanks.
Discovering Thermo Switches are no longer available did add incentive.

 

Nice! for what it's worth they are available on Ebay.

 

nice , I have the exact same problem

 

I need to do this to the sub-zero sensor in the oil pan of my 13B SE. I was wondering if this could be done.

 

Thanks for that. I had not considered Ebay.

 

The only two things I have on the 12a oil pan is the oil level meter and the sensor on the right in the second picture. I'm not sure but that may be the sub-zero sensor. All the images I find are inconclusive.

(I'm really new to all this.)

On the thermo switch, once I had enough of the broken wire exposed I checked the sensor's continuity. After soldering I re-checked to verify the connection prior to applying the epoxy.

 

30+ years of engine heat does take it's toll on wire insulation. I've had to do a number of similar interventions. Well done, sir.

 

What I tried before does not hold up to movement of the wires.
The epoxy is much to rigid and tends to break.

So I'm now trying Permetex Ultra Black. It dries to hold its shape, but still is slightly elastic. Also I'm applying the silicon to the wires as the wires are in the final assembled position.

 

On my oil level sensor, I embedded the wires inside a 1" long piece of Teflon tubing filled with silicone. Sort of a super-strain-relief.

After the insulation breaks down & cracks at the stress point, the copper wire starts to oxidize as well as getting flexed more than intended. Makes the copper get brittle.