Wiring Harness Plastic Sheathing? Options

[TINKERGINEERING]

Currently working on the wiring harness and found a couple wires in desperate need of replacement but they go through this plastic sheathing on the harness. Has anybody replaced wires through this sheathing? Should I just pull the wires out and try and jam them back in? I was also thinking I could just replace the sheathing, because it is 50 years old now, but how would I put new sheathing back on?
Thanks so much

[ClayPerrine]

I am currently adding lots of wires to my harness for the MS3Pro ecu. I have been putting them through the tunnel, and up the new snorkel tube to reach into the engine compartment.

I have found that you can use the existing wires, if they are long enough. Just pull one of the existing wires back until a section that was at the far end is inside where you need to start adding wires.

Then get a new, throw away wire, and tape it to the existing wire and pull it through the sleeve. Once it is in there, use it to pull the rest of the wires through the sleeve. The original wire is still in the harness, and you have your new ones pulled through.

Sometimes you have to break it into sections if you want to make it really go though the chassis. I can't pull wires though from the inside of the car and up through the snorkel all in one pass. I have to break that into two pulls, one from the inside to the outside, and one up the snorkel.

Hope that helps.

Clay