Clutch Won't Disengage

[adivin]

2 hours ago, Mark Maras said:

 Don't sweat the 2mm clearance. The important thing is there is enough clearance between the release bearing and the pressure plate fingers that the bearing doesn't spin with the pressure plate when the clutch is released.

Right, this is where I'm at now.  I guess just trial and error?  I'm worried that when I finally get enough clearance between bearing and plate, the clutch won't disengage again.

[cgsheen1]

Are you saying that you've adjusted the nut out far enough that it's now causing the fork to put constant pressure on the pressure plate? 

23 hours ago, adivin said:

Breakthrough I hope...while waiting for a new collar to come in, I decided to adjust the slave cylinder to what I thought was an extreme amount.  I desperately didn't want to drop the tranny again.  The rod is now tight against the fork and there is zero play in the cylinder, BUT low and behold the clutch disengages.  The car rolls forward while in gear with the clutch in.  I hope the clutch doesn't slip now.  I need to find where the sweet spot is.  Taking out the clearance and backing the nut 1.5 turns per the FSM is too much and the clutch won't disengage from there.  I have no way of measuring a 2mm gap (FSM) from the bearing plate springs.  Trial and error?  I guess this adjustment is ok as long as the clutch doesn't slip?

Just wait for the longer collar.

[adivin]

3 hours ago, cgsheen1 said:

Are you saying that you've adjusted the nut out far enough that it's now causing the fork to put constant pressure on the pressure plate? 

Yes, that is exactly what I'm saying.  I am going to play with the adjustment and hopefully I can find the happy spot.

[adivin]

Well, I backed off the adjustment nut two revolutions and the clutch stopped disengaging and there is still constant fork pressure on the pp.  I will bleed the MC one more time, and then I bite the bullet and put the longer collar in.  😞

[Yarb]

Hate to say it but your only going to find out once you have removed the transmission. You will be able to see what’s really happening, inspect the pilot bushing etc. just my 2c

[Zed Head]

I had a weird situation where the slave cylinder was leaking and I only got 1/2 of the expected travel from the cylinder.  It moved when I watched it but it wasn't moving far enough.  Could also be a leaky spot in your MC.  I would measure the travel distance to be sure that you don't have a hydraulic problem.  I think that EuroDat has published the distance that the slave piston should travel.

I haven't figured out if Nissan meant that available/possible travel was 1.38" or if the piston was supposed to travel 1.38" when the pedal was pushed.  Not clear..  I think that they must mean that it should be 1.38" when you press the pedal, since the end of the bore is open, and full stroke would be essentially unmeasurable.   Either way, it would be good for you to know the number.  And, if you do take it apart consider getting a later clutch fork and use a self-adjusting slave cylinder.  It's an improvement.

[adivin]

46 minutes ago, Zed Head said:

I had a weird situation where the slave cylinder was leaking and I only got 1/2 of the expected travel from the cylinder.  It moved when I watched it but it wasn't moving far enough.  Could also be a leaky spot in your MC.  I would measure the travel distance to be sure that you don't have a hydraulic problem.  I think that EuroDat has published the distance that the slave piston should travel.

According to EuroDat the full travel is 35mm, but the operating travel is 25mm.  I did measure on my cylinder and was only getting half of that.  I'm not convinced my slave cylinder is able to travel 25mm.  I have no leaks and I bled the mc again but no improvement.  I could hold off and get another self-adjusting cylinder just for kicks but I think I'm in denial.

[adivin]

Also the slave cylinder that EuroDat referenced is the non-adjustable type.  The throw on the adjustable type may not be as long.

[Zed Head]

23 minutes ago, adivin said:

I did measure on my cylinder and was only getting half of that.  I'm not convinced my slave cylinder is able to travel 25mm.  I have no leaks

The leak in the MC would be internal.  Unable to build pressure at a certain point in its travel, then lets the fluid back in to the chamber as the piston retracts.

The slave cylinder can contain a lot of fluid inside the dust boot without leaking.

You need to get proper travel from the hydraulics.  It's critical.

[Patcon]

I wonder if the pushrod adjustment at the master would change the slave travel?

[adivin]

7 minutes ago, adivin said:

Also the slave cylinder that EuroDat referenced is the non-adjustable type.  The throw on the adjustable type may not be as long.

Just measured the travel again with it off the tranny.  From fully depressed to full extension is only 12-13mm.

[adivin]

6 minutes ago, Patcon said:

I wonder if the pushrod adjustment at the master would change the slave travel?

I took a look.  This is where I'm at.