SteveJ

The bolts are metric. I don't remember the size.

Welcome to the forum. I see you're in my neck of the woods. I'd appreciate it if I could come by some time.

Thanks for posting the links.

On Figure BE-2, it is identified as "Switch Element". Yellow/red tends to be power for gauges. The only yellow wires I could find were from the fuel gauge to the fuel sending unit and from the intermittent wiper relay to the wiper motor. Unfortunately while all of my answers are accurate, they don't do much to provide you with the information you're really looking for.

Is it a three wire connector? Confirm wire colors. It looks like white/red, white and black. Wire colors and connectors are everything when you are asking these kinds of questions. Edit: In blowing up the picture, I see that I confused a shadow for a black wire.

I could look at another spare gauge, but that won't be until next weekend at the earliest.

It's probably the same part number as for the 260Z. When I had one of those apart, I did not notice a mechanical adjustment, but I wasn't looking closely at it. It's not too difficult to remove, open the case, and inspect if you want to, provided you don't have factory AC in the car.

I got plenty of photos of the two of you on the track. I felt bad for Andy when I saw the right side had been severely pancaked. I'll eventually get links up to the photos.

You'll need a pin removal (extractor) tool. However, I don't know which one you need for the round connectors. Edit: This one gives you options: https://www.amazon.com/Lisle-56500-Terminal-Tool/dp/B0009OR906 2d Edit: Just search for pin removal tool at Amazon under automotive. There are a lot of choices like this (https://www.amazon.com/ILamourCar【11PCS】Auto-Terminal-Electrical-Connector-Extractor/dp/B07B2P7D7L) and this (https://www.amazon.com/dp/B075KLM6R9/ref=sxbs_sxwds-stvpv2_1?pf_rd_m=ATVPDKIKX0DER&pf_rd_p=2708083022714283574)

Quick reference: http://www.carpartsmanual.com/datsun/Z-1969-1978/body-260z-280z/2-seater/door-lock-regulator-handle If you are missing part of the lock, the door lock part numbers for your car are 80502-N4420 Right 80503-N4420 Left

That is not a separate part. It is a component of the door lock. It's the same part number for the 77 and 78, but the 2+2 uses a different part.

Is there any chance the rubber brake lines at the wheels are ballooning?

So did you check the orientation of the brake calipers?

Yes, it is unusual. The typical suspects are a battery going bad and loads added to the wrong side (battery side) of the ammeter.

For me, I just would repair the dash harness, but I am hard-headed that way.