clutch fork won't move

[Zed Head]

Hey Diseazd 75mt280z appended his post to the end of this long thread.  You might be replying to Ben's Z's 2013 post?  75mt didn't describe his collar.  Nice diagram though.

Edited August 12, 2017 by Zed Head

[75mt280z]

1 hour ago, Zed Head said:

To be sure and clear - you pressed the pedal to the floor, put the transmission in gear, but the car did not move when you released the pedal?  I think that maybe you meant force but said pressure.  Pressure is what's inside the cylinders, force is what pushes against the bottom of your foot when it's on on the clutch pedal.

It's not clear, because there would be no reason to replace the cylinders if the clutch was stuck in the disengaged position.  The clutch engages the engine with the transmission.  It's kind of counterintuitive to interact with the clutch in order to disengage it, so easy to get the words backward..  You engage your foot with the clutch pedal to disenage the engine from the transmission.

Anyway, if it's stuck disengaged that would be a clutch mechanical problem, or a stuck collar, not a hydraulic system problem.

Just trying to figure out what exactly is going on.

Edit - consider also a broken shaft in the transmission.  Maybe the clutch is working fine.

The pedal doesn't engage the clutch there is no force at all. I can press the pedal to the floor but it won't go in any gear at all. When the engine is off, the lever goes into all gears without the pedal. The old master cylinder was bone dry, that is why I replaced both cylinders for if the hydraulic system is running good, there wouldn't be any leaks. The old clutch was worn down to metal, no ceramic left, that is why I replaced that. Fork is installed correctly on the ball and greased to what was recommended. Could it just be the throw out bearing collar? I did all the work myself, and all parts on the input shaft were moving correctly before I had put the tranny back on. Now the fork is stuck just the same as before I had done anything at all to it.

Edited August 12, 2017 by 75mt280z

[Diseazd]

25 minutes ago, Zed Head said:

Hey Diseazd 75mt280z appended his post to the end of this long thread.  You might be replying to Ben's Z's 2013 post?  75mt didn't describe his collar.  Nice diagram though.

Thanks Zed Head......I'll go back to my knitting now.  

[Zed Head]

15 minutes ago, 75mt280z said:

The pedal doesn't engage the clutch there is no force at all. I can press the pedal to the floor but it won't go in any gear at all. When the engine is off, the lever goes into all gears without the pedal. The old master cylinder was bone dry, that is why I replaced both cylinders for if the hydraulic system is running good, there wouldn't be any leaks. The old clutch was worn down to metal, no ceramic left, that is why I replaced that. Fork is installed correctly on the ball and greased to what was recommended. Could it just be the throw out bearing collar? I did all the work myself, and all parts on the input shaft were moving correctly before I had put the tranny back on. Now the fork is stuck just the same as before I had done anything at all to it.

It might be just the collar.  Look at Diseazd's picture.  The collar ears need to ab ~92mm from the flywheel as he shows.  Did you get the collar with the pressure plate, as a kit, or did you use your old one.

Also, it takes a lot of force to move the fork.  The length of the clutch pedal is a long lever and a leg is strong.  The first thing that I would is make sure that the slave cylinder rod is producing force.  Have somebody press the pedal while you watch it.  You can push it back in to its bore by hand when the pedal is up.  See if you can crush a piece of wood or a pencil using the pedal.  That would show you it's producing force.

I don't see any words about bleeding the hydraulic system.  Also, people have been known to install the wrong MC. Confirm that the hydraulics and linkage at the pedal are right.  The fork's probably not stuck.

[75mt280z]

2 minutes ago, Zed Head said:

It might be just the collar.  Look at Diseazd's picture.  The collar ears need to ab ~92mm from the flywheel as he shows.  Did you get the collar with the pressure plate, as a kit, or did you use your old one.

Also, it takes a lot of force to move the fork.  The length of the clutch pedal is a long lever and a leg is strong.  The first thing that I would is make sure that the slave cylinder rod is producing force.  Have somebody press the pedal while you watch it.  You can push it back in to its bore by hand when the pedal is up.  See if you can crush a piece of wood or a pencil using the pedal.  That would show you it's producing force.

I don't see any words about bleeding the hydraulic system.  Also, people have been known to install the wrong MC. Confirm that the hydraulics and linkage at the pedal are right.  The fork's probably not stuck.

Ok. Thank you for the info, you are helpful. I will test the cylinder rod. Like you say, the fork should be fine. It's something with the pressure of the cylinders I am sure.

[EuroDat]

10 hours ago, 75mt280z said:

The pedal doesn't engage the clutch there is no force at all. I can press the pedal to the floor but it won't go in any gear at all. When the engine is off, the lever goes into all gears without the pedal. The old master cylinder was bone dry, that is why I replaced both cylinders for if the hydraulic system is running good, there wouldn't be any leaks. The old clutch was worn down to metal, no ceramic left, that is why I replaced that. Fork is installed correctly on the ball and greased to what was recommended. Could it just be the throw out bearing collar? I did all the work myself, and all parts on the input shaft were moving correctly before I had put the tranny back on. Now the fork is stuck just the same as before I had done anything at all to it.

The sentence in bold italics is sometime that I would check too.

You have not mentioned seeing the clutch fork move when you press the peddle. Can someone help you to confirm its moving?

Have you adjusted the master cylinder rod correctly? If it doesn't return completly (incorrect adjustment) the hydraulic fluid will not pass from the reservoir to the cylinder.

You can tell if you have the correct (or one that should work) by measuring the distance between the fork and the bell housing. It should be around 110 - 115mm. See photo.

If you are getting less than 120mm, you are in trouble. The collar doesn't match the pressure plate. It is the pressure plate and collar the have to match and add up to the holy number of 92mm. Clutch disc, clutch fork, slave cylinder etc are for all intentions the same. With a new clutch disc and the correct collar you should be down around the 110mm or even a little lower.

The collar you should have for the 280Z orriginal pressure plate is 29mm. If you have a pressure plate for the 2+2 it will need the 25mm. 

You should be able to push the slave cylinder push rod back into the slave cylinder about 10 - 15mm. Just push firmly on the back of the clutch fork with the palm of your hand. This will tell you a couple of things: 1. The master cylinder port is open to its reservoir, and 2. The push rod is the correct length and allows for clutch disc wear.

 

 

[Arc2Arc]

Cc

Which collar would I use?

I not sure which collar you now have, but it sounds like you have the longer one. If you open the transmission link in post#8 and scroll down to the clutch forks. You probably have the left one in the right photo. Its 28mm from were the fork fingers sit to the back of the bearing. The right one is 24mm. You could ask the company that supplied the clutch for info on which collar to use.
I think, but not certain of it, that they changed from 280z to 280zx, but that could be onlt the turbo model. It the clutch is for the 280ZX then that could be where your problem is.
Chas



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