Captain Obvious

Washers and bushings look good. As Racer X mentioned... That clutch line. Haha!! When you replace it, screw it tight into the slave cylinder first. Then (after it's fully tight into the slave) put the other end into the holder bracket attached to the chassis. That will allow you to get a better routing of the rubber line with less twisting.

I mean, after all... The biggest improvement you could make to the original system would be to come up with an easy way to get variable speed intermittents, but that module has a fixed 7 second delay and would be no better than what we already have.

Well, clearly the obvious answer would be using that module to replace the original module, but I don't think that's it. TOO obvious, even for me!

Couple more thoughts on your alternator thing... First, if you find the overcharging issue happening again, you can take voltage measurements from both of those W/R wires on the back of the alternator. They should be identical (because they are supposed to be hard connected together inside the harness). If you find 15.5 on the large W/R and 12.5 on the small, then you've got a problem with that connection. Second, it IS of course possible that you've had multiple voltage regulator failures on multiple alternators. However, as the number of them goes up, the likelihood that you're got something else going on goes up as well.

I'm thinking there's a possibility you have an intermittent connection and when you move the wiring harness around to change the alternator, maybe you're temporarily bettering the connection. For the 78-83 alternator system, there should be two W/R wires going to the back of the alternator that are always hot. One big, and one small. The big W/R is power output from the alternator and the small W/R is the sense line. Those two W/R wires are connected together inside the wiring harness. I've heard of other owners finding that the connection between the two (buried in the harness) corrodes over time and becomes intermittent. That, or as SteveJ suggested above, maybe the contact(s) inside the two position connector on the back of the alternator is flaky dirty intermittent.

When you took the alternators back to the store, did they confirm the problem on a tester? Did they test them before they accepted them back for exchange? Reason I ask is if there's a poor/intermittent connection on the sense line leading to the alternator, it'll charge too high. And if it's intermittent, you might think it's a problem with the alternator, but actually it's a problem with the rest of the car.

The issue with the gibberish in the manual... The manuals were scanned to PDF on a flat bed scanner and OCRed (Optical Character Recognition). Not sure why, but the OCR process for the 75 manual (and only the 75 manual) didn't do so well. If you look at the same page FA-2 in the 76 manual everything makes sense. One last thing I think I see on your pics is that there should be a smaller flat washer on both outside ends of the larger washers. Doesn't look like you have one of those on the forward side of your car. Looks like you have the big domed washer right up against the shoulder on the T/C rod. Good luck with the covid. I don't think I'm ever going to be the same. I think I'll be OK, but different.

Torque spec for the torsion rod end nut - Page FA-2 of the manual says 33 to 40 ft-lbs. Basically, you should compress the rubber to the point where you have bottomed out against the metal sleeve that runs through the center and then torque to hold it there. Oh, and not totally sure, but it looks to me like you have the big washers on the torsion rod bushing installed backwards. They should have the convex side towards the rubber. Counter-intuitive, but that's the way they want it. Should be like this:

The wiring diagram shows three connections to the negative battery post... 1) To starter. 2) To EFI system. 3) To body. So I don't know if the wiring diagram is "literal" or "really how it came from factory", but that's what it shows. I also took a look at the 77 diagram (my year) and they only show two connections to the battery negative. My year does NOT have a dedicated connection right from the battery to the body. And now you have me thinking that maybe I should add something like that. So thanks a lot...

Well there's lots of diagnosis that could be done to figure out what the real underlying issue is, but at this point, if a starter relay makes it go away, then it sounds like that's going to be good enough for now. There is some extra stuff on the CA spec cars that gets engaged when the key is in the START position, but I don't know how much current it would draw. With a quick look at the wiring diagram, it looks like it would be just a couple more "lamp test" lights in the HVAC vent panel, but in your video it looks like that panel (and it's associated light bulbs) is not installed. Anyway, still hoping that the starter relay takes care of it. if you're looking for something simple to use to test some of the theories (and get you out of a jam like when you're sitting in the que at the store)? Run two wires from your starter into the interior. Use those two wires to short to the solenoid directly like you were doing manually out in the engine compartment. Put a switch on it in the interior if you're feeling fancy (push button start like the new cars ), or just connect the two wires together if you need to.

Oh, and... Yes, the link that feeds the ignition switch is the green one. And that schematic was originally made for 77/78. The concept still works fine, but the wire colors are a little different for 75 and 76. I'm sure you've already figured that out.

I like the video. I can feel the frustration through the screen. So I'm not sure if the click on the video is the starter solenoid or not. Can't tell from my seat. And as for the ammeter... I see the draw. If the gauge numbers are correct (and I have unknown to low confidence in the accuracy of the numbers on the gauge face) it appears that the car is drawing 20A or so when you turn the key to START. Question is... Is that a reasonable draw even WITHOUT the starter solenoid engaged? Does the ballast defeat and other associated functions come to anywhere near that when in START? I think I could be convinced that all the other ancillary functions can come close to that even without the starter solenoid. Let us know how the starter solenoid works out. I saw in one pic that your car is a manual trans. Did it come from the factory that way, or was it converted? Also, is your car a California spec? Do you know?

Oh, and adding a starter relay is a great idea regardless of the issue are having. I've seen burned up contacts inside the ignition switch caused by the solenoid current (which can be upwards of 8A or so IIRC).

Yeah, that doesn't help at all. So it does it... You walk away from the car to get help. Walk back with help. They turn the key while you have a hand on the starter, and it cranks fine that time. And the next 1000 times in a row.

Do you have access to some help in the diagnosis? Someone else to turn the key while you lay a hand on the starter to feel for the click?

I'm having a real hard time coming up with a failure scenario that would result in the issue you are having. If you've got enough juice going to the solenoid to illicit a heavy click from said solenoid, then that click indicates that the solenoid has pulled in. And if it has pulled in, the motor should spin. I guess there's the possibility that there is juuuuuuust the perfect amount of resistance in the low current primary side of the circuit such that the solenoid will move some, but not pull in all the way? I've never seen that situation, but I guess it's possible? Enough current to the solenoid that it starts to pull in, but the voltage drops along the way (wiring, ignition switch, etc) limit the current to exactly the right amount such that the magnetic force isn't quite enough to pull in all the way and engage the high current contacts. Maybe?

Wait... What? You get a loud click from the starter, but it doesn't turn? Both the old reman one and the new reman? "I can hear an audible click from the starter, and the amp meter shows a heavy draw at that moment the key is held in the start position." Are you sure that click is actually coming from the starter?

The label clearly indicates it has some sort of petroleum in the mix, and water is not even mentioned. I'm assuming that the water isn't mentioned because it doesn't have to be. I'm thinking they only had to list the potentially dangerous stuff and water doesn't count. So I'm wondering the same thing(s) as you about the mixing of water and petroleum bases, and my assumption goes like this... The base is mostly water, but it contains some petroleum compounds as well. I'm thinking they are emulsified together in the final product. The (small?) amount of petroleum compounds are held in suspension in a water base? In any event, my bottle is liquid enough to use now and I guess I'll find out in a year if adding all that water was OK or a bad idea.

Well @Mark Maras, I have to retract my previous claim that water won't work. I put a little blob of the dried out compound in a small cup and added a little bit of whatever I could find in the area. Naptha, WD-40, carb cleaner, mineral spirits, acetone. None of them did anything at all even with way more than enough mixing. Just did not want to combine at all. So, since everything oil / petroleum based just ran away, I decided to retry the other (water) camp. And after starting over with a fresh blob, I added a some water and mixed. After a bunch of mixing, it started to loosen up and once it started to loosen, it went quicker. So in the end, water was the answer, but I had to add more than I expected. It was kinda like adding corn starch wrong. You get lumps and if doesn't look like it's going to work. But if you add more water and mix enough, it eventually smooths out. Thanks for the help!!

Haha!! Easier fix than the other issues mentioned above. Good work! One of the cross beams has gone out of skew on the treadle.

Good luck with it. I'm thinking the high amperage contacts in your solenoid is pitted / eroded away. Weird that it's temp dependent though.

So @HusseinHolland, if there is no silicone blob, one other trick I've used is there might be a dent/divot on the gear where the clamp was tightened. If you look at the clamp, you'll see the dot pressed into it. That dot can leave an impression in the gear plastic as well. Kinda tough to tell... Your's might be fine, or might not. I'm sure that helps a whole lot, right?

The other bolt on my counterweight is different as well. And both his and mine look like they have not been messed with:

I was going to suggest that as well, but this is a 75 he's working on and most of my experience is with the later years. I can confirm the later years used a "Phillips" head hex on the clamp, but I've never personally been inside a 75 AFM. Can you confirm that they used the same hardware in 75 that they did in the later years? It certainly doesn't look like any other hardware I've seen on a Z, but can you confirm? Just for reference, here's the insides of my 77, It's different in a bunch of ways:

Yes... Yazaki YPC series. Best deal I could find is a guy (named waterloo_specialties) on ebay selling them in batches of 100. It's 100 male-female pairs for a reasonable price. 100 pairs ought to be a lifetime supply. https://www.ebay.com/itm/194976406675?hash=item2d657fdc93:g:K8gAAOSwEWViVya7&amdata=enc%3AAQAIAAAA4GTFG2OldlywISj0sy430UEdRG8xS7Y6%2FczZktJgokfvlm7opKNgOBWINU1dpP20TzMs%2FuMkIkuZQtGVTfRVzf3mVDICx%2F6uRZWJuQwfCEhx7u65AybljdykNewfADKEUggF%2B2gqdvIUodYa%2FWmBqDd%2BqFe4ZJ0d0xFV2UUjsNC3jI7VqL%2FRxuSjms5jTz4SNMPm8z1dCFp67%2FVWR81Sbng6nutXaKgH1n26xDZxXMlBVM6vPd%2BCetwupwNZlCdhFLjiUWNUL5QYbwS3c27YpcBDcqt4C8%2B6kWlG28qZb2eD|tkp%3ABk9SR4yYp-mQYg I bought 100 pairs a while ago and have been very happy with the whole ordeal.