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10 years after hybernation - '75 280z

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Hi tamo --


I'm looking at your video and am not 100% sure what is wrong. Your clutch does seem to retract, are you not getting enough travel in your clutch pedal?


Did you purchase the proper clutch slave + clutch master cylinder for a 75 280Z? I believe they do differ depending on whether you have a 5 speed or 4 speed, as there are different throw out bearing lengths (inside transmission bell housing). 


Also, when you installed your Clutch Master Cylinder, did you match the length of the rod with your old clutch master cylinder? This will help ensure the adjustment of when the push rod touches the piston is correct. From what I understand from my experiences, when you put your hand on the clutch pedal and push forward lightly... there should be about 1/16 of an inch travel before you feel the push rod touch the piston in the Clutch Master Cylinder.

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It's getting worse... :malebitch


After replacing clutch Master and slave and rubber hose and bleed it, I realize there is no traction from clutch withdraw lever.


What is the easiest way to trouble shoot this?

Do I need to remove engine?


It seems like either the clutch master isn't relieving pressure (not retracting completely) or there is a mechanical issue with the clutch assembly (especially in the release bearing collar and pressure plate combo). For the first issue, make sure that pedal position is adjusted correctly. That procedure is in the FSM. The second issue (mechanical problem) will require taking the transmission out, so I'd check the hydraulics thoroughly before jumping to conclusions.

Edited by Leon

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Hi spitz17, Leon,


Thank you for your advice.


I bought Clutch master and slave for '72 240z. But when I check parts number @ RockAuto, same parts are used for '78 280z. therefore, I assume it doesn't matter.


I didn't step on clutch pedal when I took video. The clutch slave cylinder is fully extended as default state. There is not push back force from withdraw lever. Therefore When I step on the clutch pedal, I don't feel any traction at all since Clutch slave cylinder is fully extended.

That's why I assume it's mechanical problem on crutch itself, not hydraulics issue.



I think accurate behavior when stepping on clutch pedal is like this.





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On MSA's site, it sells two versions for 70-72 and 73-83. However, I believe the 70-72 has the Series 1 return spring, which you do not have. So I think that the one you have is correct.


After re-reviewing your videos, I do think it is a problem with the clutch collar or bearing. You may just have to drop your transmission to get this done. The clutch collar is spring loaded, which engages to clutch... It looks like yours is overly flimsy!

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Too short of a throwout bearing collar for the pressure plate would be my guess.


In order to get the car up high enough to get the transmission out, I think it needs to be at least 18" off the ground (I think duragg posted the numbers from the many times he's had to do this). If your driveway is level, you're OK. Just make sure your jackstands are tall enough.


Might as well put in a new clutch and consider a lightweight flywheel.

Edited by Leon

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Having done the transmission on my Z before, I'd agree with Leon. The car has to be at least 18" high, and also keep in mind that using a regular jack may need more clearance to get leverage on jack's bar. Tamo3, I see that you are in the San Jose Area. You are more than welcome to borrow my transmission jack I used for my transmission drop. I am in Los Altos, and I may even be able to help you, if you're open to it.


I also agree with Leon that you should probably do a flywheel and clutch job since you are in there, but I'd also add to do the Rear Main Seal of your engine too. These are prone to leak and destroy clutches... Just my 2 cents. :)

Edited by spitz17

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Thanks for your advice!


Spitz17 for your offer! I really appreciate that! I will let you know once ready to drop tranny.


Based on Leon and Spitz17's recommendation I would like to change clutch too. I have brand new OEM 240z clutch bought @ ebay long time ago. Do you think I can use it for 280z or do you have any recommendation?

Some people said Exedy is good, other people said ACT is good one.

For mainly street use, I don't know what is the better option.


I think this is the great opportunity to swap transmission from 4 speed to 5 speed too.


I was working on rebuilding 280zx tranny but encounter issue for removing nut from mainshaft and stopped....



I grinded tools to try to bend the nuts, but I think should grind the nut itself.

I should re-prioritize and finish rebuilding tranny first at this time to move forward my project.



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Thanks for your feedback.


I will measure flywheel size and clutch size.

Also bearing collar size.




If size did not match, I'm plannig to get Exedy + Fidanza flywheel.




Did you get yours from eBay?


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Thanks Leon, I will read over.


Tonight progress... not so progress made.

Got Stronger Clip Plier at Autozone.


It has Internal / External combo with exchangeable tops. 2mm tops is looks promising durability :icon54:




However, it kept slipping with tranny oil and cannot grab the clip...



For brake rotor with spacer, I bought M10x1.25 40mm bolts at OSH.




This bolt is the best size to fit slotted rotor with 9mm spacer to hub.

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Fighting for ring pin removal from the reverse idler shaft.



Waiting for 2 days, got new ring pin plier Tekton 3574 from amazon.com for $5.88


First try, it broke the tip! Cheap made in China product is not durable enough.


I read again datsun garage website again and realized that the author recommend Stanley-Proto J250G lock ring plier.

 This ring plier is different design from regular ring pin plier.



Sure, it is heavy duty construction and using slotted screwdriver to push, finally, I could've removed the ring pin!




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While waiting for the ring pin plier, I was working on coilover project.


First of all, I try to cut the spring porch using grinder. It takes too much time and I replace disk to cutoff disk. Using right tool  is saving so much time.



However, I leave too much metal for grinder. It takes about one hour for grind off extra metal to smooth up just one of the strut.



For rear strut, I still haven't remove the drum disk brake. In order to remove drum disk brake, I need to remove the Hub.


When I read FSM and Blue's work, it sounds harder to remove the rear hub.



I read some other post from somewhere, using impact wrench is much easier to remove the nut.

Grind the inner nut of hub and use impact wrench to remove.



Then using 12t shop press from HFT, to push out the hub.



So far so good for the strut modification.


I decided to go coilover conversion uing Bilstein P30-0032 shock following thehelix112's instruction.

I don't know whether GroundControl Coilover Conversion kit was available at the time when thehelix112 did his work. When I calculate the cost of the parts, it seems like it almost same with GC coilover kit.

I wonder I can use GC's coilover kit with Bilstein P30-0032.




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Tamo, I have been reading through your build thread and I think you should get a clear universal fuel filter and install it inline immediately after the tank/before the fuel pump. After sitting for that length of time with old fuel in the tank, there is most likely some amount of sludge and/or rust piled up in the tank - My 77 280z sat for about a year with maybe a gallon of gas in it and it had some rust and sludge deposits in the tank. I installed one of those cheap universal fuel filters and it has collected about half a tablespoon of sludge/rust in it after a few months. The filters are available at many parts stores and online, usually for a few dollars.

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Thank you for your reading my project thread and giving good advice. I was planning to do total clean up for gas tank before put my triple weber.

Previous owner filled up gas tank almost full and when I remove old gas, I didn't see any sludge at all.


Once tranny is done, I will replace fuel filter and fuel tube before running.

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Just small update.

After ring pin is removed, banging mainshaft to remove counter gears.



On the mainshaft, there is Over Drive Gear Bushing that prevent me to remove the over drive synchronizer hub and insert retainer.



There was a discussion about suitable spark plug.

I got B6ES and BPR6ES-11 to compare.


For my 280z ’75, B6ES seems to be the good one. Decoding the plug name BPR6ES-11…

  • B: Thread diameter 14mm
  • P: Construction. Projected
  • R: Construction. Register Type
  • 6: Heat rating. Hot (2 – 11)
  • E: Thread Reach 19mm
  • S: Firing End Construction. Standard center diameter 25mm
  • -11: Wide Gap 1.1mm (0.044″)



Left B6ES, Right BPR6ES-11



Left BPR6ES-11 with wider gap, right B6ES



Left BPR6ES-11 with Register Type tip, right B6ES


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Thats the worst part about sludge buildup! In my (albeit limited) experience, you cant really tell that its in there until you either purge the tank with acids or you blow your fuel pump and clog your lines. Guess which one was the experience I had...


Keep up the good work, you inspire others like myself to keep going on our restoration projects.

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Thanks for your advice! I will make sure to replace Fuel filter before running engine next time!


small progress.

Finally all the gears are off from the shafts.



I need to make sure to memorize the direction of 1st & 2nd gears's syncro.



The bearing inside of 1st & 2nd gear syncro has brownish color... rust??post-25175-0-10637100-1369351696_thumb.jpg


I bought rebuild kit @ ebay looong time ago, before acquired this close ratio tranny.

The syncros should be all 4 same thing. but 2 of the looks new, other 2 of them seems like used one.... :icon51:


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Getting advice from duragg,  I figure out my unkown tranny's gear ratio from the counting teeth of gear.


Main drive gear = 21

1st = 33

2nd = 27

3rd = 25

5th = 24

Reverse = 36


Counter drive gear = 32

1st = 14

2nd = 20

3rd = 28

5th = 45

Reverse = 15


Here is the formula of how to calculate gear ratio.

Gear ratio = (main driver gear) divided by (counter drive gear)

1st Gear ratio = (1st gear) divided by (1st counter gear) divided by Gear ratio




Gear ratio = 21 / 32 = 0.65625

1st gear ratio = 33 / 14 / 0.65625 = 3.591836735

2nd gear ratio = 27 / 20 / 0.65625 = 2.057142857

3rd gear ratio = 25 / 28 / 0.65625 = 1.360544218

4th gear ratio = main drive gear / counter drive gear / 0.65625 = 1.000

5th gear ratio = 24 / 45 / 0.65625 = 0.812698413




Comparing with close ratio and wide ratio of 71B, my unkown tranny gear ratio is much wider than wider ratio. I think it's not worth to  spend more time on this tranny...


However, I learned a lot from this tranny and get so much experience and confidence from braking this in a parts.

I have '77 FS5W71B tranny. It's wider ratio. But I can install that into Z sooner.

Edited by tamo3

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I realize that if I change main drive gear and counter drive gear with other one, my "unkown" 5th gear seems like useful.



If I swap my 5th gear and 5th counter gear to '77 FS5W71B(wider ratio), my Over Drive 5th gear ratio become 0.7515 which is closed to "closer ratio" 5th gear ratio of '81-'83 FS5W71B, which is 0.745. It's good finding. Wider ratio 5th gear is 0.864. I can get better high way millage with this swap.




I think my "unkown FS5W71B" 5th gear and counter gear of 5th are interchangeable with wider ratio of FS5W71B. Will try this weekend.


Edited by tamo3

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