Oblithian

SOLUTION: You were correct, the sound was the outer U-joint of the PS axle-shaft. When I pulled them it was very obvious it was bad. I replaced both of them and the sound is now gone. (The hubs also have too much play. We'll see if it's the spindle or the bearings, or if it just needs tightening). I will add the video or images here when I get around to it. Thank you all for your help. P.S. True, in some years the propshaft/driveshaft u-joints are listed as 'not replaceable' like 1975 (mine). However, they can be replaced yourself if you can track down the right parts using measurements, or just have them done at a driveline shop. I have done both. There is a video on me doing that, but it's not immediately relevant to this thread so here is one on that subject for anyone coming to read: https://forums.hybridz.org/topic/100835-280z-driveshaft-u-joints-irreplaceable/

If we are all converting it to something non-stock anyway. Why don't we all try to find some alternate calipers that would work with the rotor dimensions but with a more suitable handbrake setup? Perhaps something even cheaper and more widely available? The adapter plate is custom, but it is also the simplest component to replace/modify as needed.

Update: So I can't say for certain what is causing the sound, but after having inspecting all the parts for play, I can say the wheel bearing needs replacing. So... Maybe it is an early warning sound? Or maybe the bearing is fine and there's just too much play in the hub.

Thanks for the suggestion, I have replacement u-joints from... several years ago (I wanted to have them handy if/when they went. The driveshaft u-joints had gone before I bought the car). If it is the shaft itself... Then I guess I have an excuse to make the 300ZX upgrade.

While driving around the coast I noticed my car (1975 280z 2+2) has started making a repetitive spring-like squeaking sound that gets faster as you drive. But it only makes sound under acceleration, and only when driving forward. Also, it is less noticeable at higher speeds. However, it isn't that loud. So, it could be that it stops, or it could be that the engine and road noises drown it out. It sounds like it is coming from the PS rear-quarter? The car does not squeak when going over bumps or when I bounce the corners of it. I am on a trip at the moment so I can't examine it. Does this sound familiar to any of you? At this point I am thinking, brake... maybe axle related?

Thanks, yes I am aware warping is caused by overheating, that wasn't the clearest writing. It assumes the reader knows the context by that point (I will amend the prior comment to make it clearer). A thermostat that is stuck closed will cause increased pressure from the pump, amd have increased pressure from the excess heat. coolant that isn't flowing, isn't cooling, but causing rapid overheating (though slower than no coolant). As an update, I replaced the head gasket (I didn't bother measuring the deck) but the radiator is no longer losing coolant volume and is no longer leaking into cylinder 6.

No I just left the stock dimmer, I thought about installing an adapter but the LEDs I went with aren't bright enough to need to be turned down (I may buy brighter ones, but they're at least bright as the stock bulbs with the green lenses). The hazard sounds like there is a short, apparently it is common to get one in the indicator sockets? So I would check them first but a short could be anywhere really... I mean, if you already need a fuseblock maybe check again after that's replaced. Best bet for a stock switch is some of the local datsun clubs, some people just have stacks of parts.

So, I ran the coolant system pressure check, and there were some leaks at the hoses (but only under testing pressure). I tightened them up, and the leak moved to another hose that looks like it was replaced. I got them all and it seems to have stopped the leaking, and definitely holds pressure now... though perhaps it will find a new path out. I pulled the thermostat and it had been sticking, to my knowledge it was fairly new (the previous owner said he had just replaced it, and it was not original). I manually depressed it a few times and it seems to work now but I had already bought a new one... and it seems untrustworthy as it is. Hopefully I don't have lasting damage. It would suck if my head, deck, or cylinders had warped because of the damn thermostat causing excess pressure/leaks and overheating the engine as a result. On the plus side, I now have a thermostat more suitable for the cold climate (180F vs 160F that was in there), and it's high flow.

Glad my confusion has helped someone.

So, my car ('75 280z) had a coolant leak at the watercock. Pulled it apart, replaced the gasket, put it back in, no more dripping. But my car still loses coolant inconsistently and I have no real ideas where it may be leaking from. I get a whiff of coolant in the cabin when the heater is on, (esp under heavy load) but pulling the carpets there is no evidence of leaking (I am driving without them just incase). I can leave it parked and idling for hours with no spots on the driveway and no visible leaking. No sweet smelling exhaust, no white smoke. Judging by the coolant levels it isn't even leaking... until I drive it. It's not leaking intothe crankcase, the oil is always fine (and the level unchanged). I am wondering if the thermostat is broken and the higher pressure and heat under load is causing a slow leak somewhere exclusively while driving. If I can find a pressure tester maybe I can force a leak?? Has this happened to yours? Do you have any suggestions? any secret places where large amounts coolant can accumulate inside the car without my noticing? I ordered a high flow thermostat and some gaskets for the housing, I am going to install them and while the coolant is drained, pull the heatercore and inspect it, it's not putting out a lot of heat either.

Ok, so when I bought my car the bearings were going in the U-joints, and I had them replaced. That was a bit of a fuss but basically, take it to a shop that specializes in driveshafts don't waste your time anywhere else. They swapped them out for a 'staked-in' / '4 grooved' design within 2 days and I have been using them without issue for almost 5 years. Alternatively, RockAuto seems to stock U joints for many of the model years now... except 1975. Which is mine ('75, 2+2). So when my u-joint snapped (due to an akward situation where I had to floor it over a railway crossing to merge), I needed to get another set but didn't want to spend the same ammount as getting another driveshaft. So, here are the measurements I got: 0.945" (cap diameter) and 1.637" between the ears and 1.526" between the clips on the u-joint they installed prior. The closest match I found was GMB 220-7010, 0.945", 1.535" it is available on Summit Racing. But given I don't live in the US, the lead time plus the shipping cost made it undesireable (oddly walmart.com also lists them, but they are out of stock. Maybe calling in they can order them in in Canada, I didn't bother checking). The shop I went to last time ordered me one in, Part no. 430-11A Rockford But they look like the same as what's in there. Its dimensions are: ~0.947", ~2.335" overall length, ~1.697" from the outer edges of the ring landings, the center body is ~0.860" across. The biggest downside to these are the grease fitting, which is a weird dimpled design I haven't encountered before. So you will probably want to get some regular zerks. Anyway, the non-serviceable, unservicable, non-replaceable, thing is definitely not accurate. Here are some lookup sites: https://www.gmb.net/u-joint-lookup/ https://www.moog-suspension-parts.com/universal-joints-ujoints.asp https://spicerparts.com/resources/measuring-u-joints https://neapco.mycarparts.net/show_attributes/22 And this is what installing them looked like:

Thank you very much! Of course the ones the previous owner wore out would be the ones I can't swap. To answer the other question, easier yes. Cheaper no. I have two transmissions, and will be replacing the bearings and syncros come summer in the 5-speed. Unless someone who happens to be close by wants to trade me for my 4-speed, I would probably have to buy a whole 280zx to get another 5-speed. The gear ratio change intrigues me, I will mull that over.

If there end up being aftermarket gear sets let me know (and maybe I can save myself some effort) This build is still in the planning stages. So I am asking now before I pull two transmissions apart. Are there any differences in shaft diameter between the gear boxes, (or other differences for that matter) which would prevent me from swapping the 1st through 3rd from a F4W71B 4-speed to a later model 5-speed? (In short, are the gears compatible?) If there is already a post on this I apologize. I could not find anything searching, and the search function kept breaking itself.

So to clear up some confusion. Going from a 4-speed ('75) to a 5-speed ('80) is a direct swap. However, there are a few differences to make note of that you may find. The newer transmissions do not have the neutral safety switch* (which doesn't really matter mine didn't work anyway, may install one on the clutch). The module with the flat connector pins is the safety switch, the module with the round pins is the switch for the reverse lights. One of the bottom bellhousing through bolts (for the plate) is longer on the newer 5-speed. So save that or order a new one. Shifter designs change but they are 100% compatible. Threading the original 4-speed starter bolts into the newer transmission was not as smooth as it should have been, maybe import those as well. The speedometer gear is (as mentioned various places) matched to the differential. So if you aren't changing the rear end, use the original gear. I.e. use the gear suited for the diff you have. Now what is not mentioned: Pay attention to the orientation of the speedo gear retainer. The gear (or cog) is offset so if they are different you will have to use the speedo gear housing from the new transmission. Knock out the retaining pin on each (be careful they are easy to lose), swap the gears themselves, then put the pin back in. Removing the whole speedogear from the transmission (again because of the offset) if you is easier twist it slightly to disengage the gears before pulling. There is some question as to compatability with input shaft sleeves, if any of you know please clarify? It seems to work fine with the original clutch and bearings are the same. I also have a 2+2 (though the donor 280zx may have also been, I don't recall).

Or if your 5-speed was scrap and a 4-speed was all that was available. ...or someone is lazy and wants to shift less? But if you want to do it, you follow the same procedure... I would check out the gear ratios of each transmission on xenon (I think that's right).

hmmm. That seems less precise than I would like... But I will give it a try, thank you for the suggestion.

I am in the middle of some bodywork, but before I can re-assemble my '75 280z I need to replace the foam pieces that brace the front fenders and outer door panels. Mine had all either dissolved or were torn when the panels were removed. Does anyone know the factory thickness of the foam so I can find a suitable replacement?

Both before and after I changed them? I suppose it's possible the previous owner and I made the same mistake. I also noticed the PS strut is sqeaking when it rotates unloaded... combined with the squatting, definitely time for a new set. Until then, please feel free to throw more ideas for me to try (the bracket bolts are tight by the way)

I located the issue, and forgot to update the post. My apologies. So the issue was a factory mis-wiring (Apparently Morbias' had the same issue). The green and white (Gw) from the tachometer ran to the red and blue (Rl) on the dash harness. Either the dash side harness was mis-wired, or the tach. An issue one would never discover with incandescent bulbs. So whoever made the mistake, at least it was harmless for 43 years hahaha. I just undid the two pins and switched them. (Which was easier than pulling the bulbs, let alone soldering them again. I would highly recommend this solution if you ever go to replace your LEDs... 100 years from now) Problem solved. Thank you for your assistance, even if I didn't end up using it. Out of curiousity, are anyone else's tachometer connectors mis-wired? ...or is it a mixed bag, where that one guy (we'll call him Doug... Though Toshi is more likely) messed up all the ones he happened to work on, but all of the other employees did it correctly?

1975 280z, I apologize if this is obvious but it's 2 AM and I have been working all day. I just pulled my dash, and replaced all of the gauge bulbs with LEDs. I tested them all, however, upon putting everything back together... The tach's illumination doesn't work (just the tach, and just the illumination, the gauge, signals, high beams, etc. all work). I pulled it twice, tried reconnecting all of the tachometer's connections. I also tried the harness box, and the connections under the steering column. Where do you guess the issue lies? (and incase I was unclear, it was working just fine before), I am going to do electrical testing for the dash harness, and the tach. But it may be a while, before I have time again. So please throw your ideas below. **So I finally uploaded how I dealt with this:

Perfect 👌

Thank you! Do you think .460" is ok?

I noticed my steering wheel doesn't return to center after turning right. The wheels are aligned still, and there is no play, simply off by about 15 degrees on return. The cause is clearly the rack shifting. Any thoughts on what might be causing extra resistance on the front right wheel? (perhaps a common problem, familiar to the s30 veteran) I replaced the rack's bushings. Not only were the old bushings fine, but they didn't solve the snag. The issue started when I put my wider tires back on (they are 215, but there is no interference), clearly the extra load/resistance is adding enough difference on the failing component to causing the rack to hold slightly right (until I turn the other direction). My thought is strut bushing or bearing (my other vehicle had the same issue when I didn't replace the old strut mount but added heavy duty springs). 1975 Datsun 280z (unmodified)