JTCN

Hi, had my driver side glass shatter on me today and am having some trouble sourcing a new one. If anyone has one they’d like to sell or have a parts car they could pull off of for me to buy that’d be great. Also not sure exactly which years of glass will fit in my 75, I know there were changes throughout the years of the car but I read some conflicting things so far. If any well knowing Z guys can chime and help me out with that I’d appreciate it. Thanks!

The springs: https://zcardepot.com/products/coil-spring-set-stock-and-lowered-240z-260z-280z?variant=21384265269361 I'm planning on installing new springs and struts and I've found this option. I don't race my car and my suspension is totally stock so far, I feel my springs and struts are fine I'm just looking to lower it. I want a 1.5 or 2" drop, I like that the springs I've linked seem linear and not progressive. They don't give much of a description of who makes these springs or where they come from though. Has anyone used them? Would you recommend them? I like the amount of drop some people get with the Tokico springs but we all know they're discontinued. I don't think I'll go the eibach route because I've been reading that they don't drop the ride height much. Also if anyone's running other brands like vogtland or STAGG etc. let me know what you think about them.

So I was on my way home tonight when all of a sudden my fan belt snapped. I was left stranded and had to pull in to a little parking lot and leave my car because it was overheating. I had a friend pick me up and I'm at his house for the night until tomorrow when we try to find a new fan belt. But I know in the process of installing a new fan belt you have to remove the ac belt. I really dont have time or the tools to spend installing 2 belts before my car gets towed. Can I drive without an ac belt? My plan is to just loosen the idler and pull that belt off to install the fan belt, and just drive it with only the fan belt on until i get home. The car is about 15 miles from my house. I just don't want to mess with putting the ac belt back on because it can be hard to work on my car with the very little space between the fan and radiator.

Well this is strange... lmao I'm back outside after eating dinner and first thing I do is turn the key on. I heard the blower motor running and I was about to turn it off but decided to start the car anyway. For some reason I decided to feel over the defroster vent and oh my god theres warm air. I don't know how I fixed it but I guess I must've plugged in a vacuum line that I didn't notice was unplugged. I took them all off under the heater controls and plugged them into the right nipples on the hvac control unit. I'm gonna shut the car off and come back later tonight to make sure it's still working LOL. Maybe a datsun loving goblin came and fixed it while I was inside. Weird.

So I chased vacuum lines some more today and all the lines are fine. I found all the lines from the manifold and dash pot to the solenoids, to the vacuum bottle, through the firewall, and under the heater controls. Not a crack or split on any of them. All still soft and flexible. I've done more research and it seems that on '75 cars the heater control valve is solely cable operated. No vacuum except for the flaps that control airflow. Since the defroster/floor vents in my car never blow air on any setting, I'm guessing it's the vacuum controlled doors. But if all my vacuum lines are fine then what's the issue? What do the HVAC solenoids actually do? How can I test them? It's obviously a vacuum issue. The question is what's failing in the system to cause my problem.

Alright I'm back from round 3 and we're finally getting somewhere. I removed my glovebox and I can see clearly that when I move the mode select lever, the heater door opens. So no cable binding or broken cable issues there. So what is actually vacuum controlled? Are there seperate doors that use vacuum on 1975 cars?

Just got back from round 2. I can't stay out there for long because my fingers go numb and useless. Anyway, I stuck my phone into the empty radio slot and recorded a video with my flash on. The cable to the temp lever is connected and works fine. I could see the cable that's connected to the climate mode selector (REC, DEFROST, AC, etc.) I could see pieces moving in there everytime I switched the mode. The cable was pulling them through the modes and they would click in place. I was only able to see one vacuum line in there though and it was small and hooked up properly. I didn't feel or hear any vacuum leaks coming from there. Is there any way for me to check the HVAC solenoids? Could they be seized? I followed all the vacuum lines going to them and they're all connected properly and not missing. I found the lines from the manifold>vacuumtank>HVAC solenoids>line to the firewall. After that I can't tell. I'll have to cut the tape around them to check if there's any tears/leaks along the lines but otherwise they're solid. Edit: I cracked open my hayne's manual and it seems to me that some of the heater system is accessible through the glovebox? I'm going to try removing it and find out.

It snowed today in Louisiana and it reminded me that my heat hasn't been working, currently typing with numb fingers. Here's what I know: No heat comes out of any vents no matter what setting. Outside temp air is blowing through the center vents and the side vents no matter the setting. I got the car to operating temp and felt the heater hoses to the firewall, both were hot to the touch. I checked the vacuum lines from the manifold to the heater solenoids and they were connected fine. The line from the solenoids to the firewall is fine too. (Haven't checked inside dash yet.) It's possible that I might've unplugged a vacuum line that runs under the dash to the AC/Heater unit. I've pulled my radio and my center console out plenty of times. Might've snagged something. Since I have hot coolant flowing through the heater core and the hoses I don't think it's a heater core issue. I'm suspecting the climate control panel or something connected to it. It's my understanding that when you switch your climate control to heat/defroster it should immediately pump air through the defrost vents/floor vents. Mine always blows through the center and sides on any setting. Also, My lever that controls the "Hot/Cool" temp of the air coming through feels really bad and not properly set up. Hard to explain but it feels almost spongy and doesn't stay where I put it. I read that it's a cable that controls this and I might have to adjust it. Also possible that the door that controls which air gets blown through the vents is stuck? Could the solenoids that control the heater be seized? I haven't tried checking all of these yet because I'm really not looking forward to pull my dashboard out. I don't have a radio installed right now though so maybe I could access this through that hole? I'm just looking for someone that maybe had issues similar to mine that could provide some insight. I HAVE got my heater to work ONCE before, and I don't know how I did it. It was last winter and it was a seriously cold night and it just worked. I had heat pumping through my defrost vents but nothing since then.

Update time. My new driveshaft came in today, this time with the correct bolt pattern. Installed it in 30 minutes, went to the gas station, and took the Z for a long drive. It drives perfect now. No shaking or rattling noises, just smooth and slow Z power. It made me realize how slow my car is when I don't have a shaking and rattling deathshaft spinning at 3000 RPM under me. Thanks to NewZed and everyone that helped.

Thanks man. I'm just going to deal with the gap and check it everytime I have my car jacked up. I have a bigger problem though. The new bolt holes don't line up with my diff flange. The new DS bolt pattern has slightly more space between the bolt holes then my old one, so I can get 2 bolts in on the same side but I can't get the other 2 bolts in, because the DS holes and diff holes don't line up. So we called the place I bought the driveshaft and they're claiming that it doesn't make sense, and that for a '75 280Z coupe the driveshaft should fit. Also the bolt holes themselves are larger than on the old DS. I can wiggle the bolts around if I slide them in. I don't see why datsun would change the distance between the holes for no reason. Maybe a Z expert can chime in on that. So now I need to find out what year diff I have I guess? Did certain years of S30 differentials have different bolt patterns on the flange? It's possible my diff and driveshaft were switched out at some point in it's life, but I don't know what year it was switched with. Also the new driveshaft is half an inch shorter than my old one, but it doesn't make much of a difference. I'll go take measurements of my old DS bolt pattern to help find out what kind of diff this is. Then I'll edit them in this post. Edit: I measured the distance between the bolts diagnolly from the center of the holes and got 2.75". I also found this pic of differential flanges, mine is exactly like the left one. While I was doing this my dad got a call from the driveshaft shop and they said they found a flange with the same pattern as mine, and are going to custom make me one today to fit my diff flange. So hopefully everything works out and we don't have to do this a second time. Edit2: I just found out that I might have an R200 diff. I found comparison pictures between an R180 and an R200 and the cover on mine looks just like the R200. So that explains why the driveshaft shop had such trouble. Also, I don't think it's an LSD. With the car jacked up if I spin one wheel the other wheel turns the opposite way. Edit3: I'm only updating this still because I think this info will help people that might get in a similar situation. A lot of this seems obvious by now. I found out that from 70-78 S30s all use that differential flange on the left. Except '75 S30s, they use the middle flange. When I ordered my new driveshaft I told them my car was a 1975 280Z manual coupe, and that was that. Never occured to me that my diff might've been swapped. So they shipped me a driveshaft meant for that 75 Z flange. Since my car has an R200 from some other Z/ZX it didn't fit, and here we are now. I'll get my new driveshaft with the proper bolt pattern soon and then everything will be fine. Here's where I found the pic and the info on S30 diff flanges. http://jagsthatrun.com/Pages/Parts_DAT_driveshaft_flange.html

Somehow my driveshaft got here unbelievably fast. Seriously only took 1 day and it's here now. So I just removed my old driveshaft and found a problem. My old DS has a dust cover over the slip yolk, my new DS doesn't. Do I need a dust cover? I've been trying to remove the cover from my old DS by hammering at the seam with a flathead and hammer trying to seperate it from the DS. I see that a lot of 280z driveshafts being sold online don't have dust covers. Is that because they're not needed or because they assume you'll just use the cover from your old DS? I need to know if I need a dust cover on my driveshaft before I install it tonight. I definitely don't want to have to do this twice. Here's a pic of the driveshafts.

Yep, and I had to buy a whole new driveshaft today. Driveshaft shop near me quoted $200 for each end of the driveshaft. Then I would have to switch out the differential flange to mate up with the new yoke they weld. Which is ridiculous considering the new one I bought is like $300. Oh well at least I'll have my Z driving again and not wreck my driveline in the process.

Uhh... bad news. I got under the car while I had it still in the air. I found the problem. Let's just say my driveshaft definitely DOESN'T feel tight and I'm a big dumbass. The driveshaft ujoint on the diff side is severely messed up. There's a lot of play on one of the cups when you wiggle the shaft. I recorded it, here's the video. https://www.youtube.com/watch?v=bIL4z48Ayjo So when I'm going down the road the driveshaft starts spinning up and this ujoint slaps and rattles the driveshaft the whole time. I don't want to drop $300 on a new driveshaft. So I'm going to call around and try to find a shop nearby that can machine in new ujoints and balance the driveshaft. Hopefully for cheaper. Thanks to all you guys for the help. I wish I would've checked the driveshaft closer and noticed before I ripped out my halfshaft lol.

I ripped out my driver's side halfshaft today to check the ujoints. They feel totally fine, no play at all and felt firm on the hub side and the diff side. There was a lot of grease buildup around the ujoint on the diff side. I don't know if it's from the ujoint itself or the diff though. I don't think I'm going to take out the passenger side halfshaft because it feels just as tight as the drivers side. Honestly I'm pretty bummed it wasn't that simple. Now I guess I'm going to wait until I go to the trans shop and see what they think instead of messing with this thing anymore. If they say there's a problem with the diff after it was rebuilt not even a year ago I think I'm gonna scream, lol I'll probably get all my wheels balanced too. Yeah it's not enough play in the diff to worry about. I felt it again today and I heavily exaggerated how much play it really was. Trust me there's no more play in the wheel lol, I replaced the bad stud. Wheel is now firmly attached to the axle and won't be flying off soon. So if it's not the halfshafts, what is the problem? I guess the bushings are the next thing I would worry about. I don't think it's my driveshaft but I'll find out at the shop.

I just found a video of a Z that's making a noise VERY similar to mine. https://www.youtube.com/watch?v=Dz84sFQBA1c It's similar in the way that it's some kind of rattling/knocking noise in the rear end. In the video his is a lot louder than mine and more pronounced. The video description says it's from one of the halfshafts, and that it was a bad ujoint. I'm going to take my car to the transmission shop this week and ask them to check out the halfshafts. I think this is my problem.