Which Clutch Slave Cylinder To Buy?

[EuroDat]

I googled "datsun 240Z slave cylinder" to check what was availabe. The first hit was a shocker from a webshop for Z parts. The parts are a mix match of the early and later types.

Here they show a later type slave cylinder without the spring anchor point (red circle) and the non adjustable push rod (blue circle). Then they simple supply a spring (green circle) and describe is as early OEM nos parts.

 

Early looks like this:

 

Later type looks like:

[adivin]

On 10/11/2021 at 12:21 PM, EuroDat said:

If you use the later version with the adjustable push rod, adjust the push rod as follows.

1. Assembly slave cilinder with push rod. NO return spring.

2. Adjust the pushrod until there is no free play.

3. With your hand behind the clutch fork push the push rod into the slave cilinder. It should travel approximatly 10 to 15 mm Into the slave cylinder. See diagram distance "S". Note: S is not 35mm. That is slave cylinder stroke or travel.

4. Adjust the push rod until this S distance is reduced 2 to 5mm. It must not bottom out.

5. Lock the push tod locking nut.

Where is this diagram?  I don't see it in my FSM.  My Fig. CL-16 is for the master cylinder.

[Zed Head]

It would be in the FSM's for the later year Z's.  Maybe 73 and after.  Actually, I just looked and 73 and after is the non-adjustable type.

[EuroDat]

Zedhead is corect. They changed the slave cylinder somewhere around July 72. All the manuals after that will have the not adjustable type slave cylinder,but it could have a different figure number.

The 240Z 73 manual has this figure nr. CL14.

 

And the 260Z shows this diagram with fidure nr. CL16

 

Reading my step 4, I will changed the text to avoid any confussion later. The objective is to remove any play in the mechanism, but not to completly compress the small spring. When you adjust the push rod to remove all the free play, turn the nut another 1 to 2 turns and lock it into postion using the lock nut. Then check you can still push the push rod into the slave cylinder about 10mm (distance "S"). The distance "S" will reduce with clutch plate wear.

[adivin]

Ok, I am thoroughly confused.  My car with 12/71 build date came with the adjustable type and return spring.  The replacement I recently purchased is below.  It has the hole for the return spring, but came with no spring.  I do not have my original spring.  Can I use this slave cylinder without the return spring?  If so, how do I adjust it?

 

[adivin]

Ok, I found the original return spring!  Still not sure how to adjust.

[Zed Head]

They don't make it very clear but the "self-adjusting" slave cylinder has a longer bore (I believe, that's why they call it out and describe the self-adjusting operation) and an internal spring.  The "S" that they show is the possible stroke area, not the working stroke.  There is actually a lot of information in the drawing if you stare at it long enough.  You don't need the external spring and you don't need to adjust it.  As long as you have the correct match of throwout bearing sleeve/collar and pressure plate (92 mm).

Here is another version from 1976 of the text that EuroDat copied from 1974.  Basically what Nissan is saying is "we fixed the slave cylinder so that the risk of poor adjustment is gone".  No return spring necessary, no adjustment necessary (because "S" is long enough to take up the disc wear).

The match between TOB sleeve and pressure plate is very important though.

Edited November 7, 2021 by Zed Head
punkshuashun

[adivin]

I don't have the self-adjusting.  I have the adjustable slave cylinder.  The FSM instructions are not making sense to me.  Specifially, "tighten the adjusting nut and eliminate clearance between the top of the withdrawal lever and release bearing."

[Zed Head]

5 hours ago, adivin said:

Can I use this slave cylinder without the return spring?  If so, how do I adjust it?

I see your problem now.  Wasn't sure what the concern was.  But you're kind of at the point of just adjusting based on the principles of operation.  You don't have the full set of original parts.

I think that what you have is a self-adjusting cylinder with a rod that is meant to fit the clutch for the old adjustable style.  So you don't need the spring.  The only reason to use the adjustable rod is because the clutch fork won't take the new style of rod, because of the hole.

I think that you'll need to study the original procedure and realize that the external spring pulls the piston all the way to the back of the bore on the old style and then they have you loosen up the rod length just a hair so that it gives maximum stroke, but doesn't wear out the TOB.  So what you could do is adjust the rod length so that the piston is pushed back all the way then shorten it enough to give you that "S" distance shown on the drawings for the newer style.

Or, just match the match the length of the newer non-adjustable rod.

If you haven't installed the transmission yet, you could change the fork to the later style and use the non-adjustable rod.

It's a judgement call.  There is no Nissan procedure for it, I think.

 

[Mark Maras]

  I prefer the adjustable one. First adjust the clutch pedal to the proper height. (specs are in any repair manual)  Without the spring attached shorten the rod until there is slack in the lever movement. Now lengthen it until there is about 1/16" of slack before the lever (and r. bearing) puts pressure on the p. plate.  If there's no gap the r. bearing will continue to turn with the p. plate. Now the clutch pedal should have a bit of slack at the top of the stroke before you feel the p. plate resistance and should go down far enough to release the clutch. The bottom line is, if there's too much free play at the top of the pedal stroke and the clutch won't fully disengage, lengthen the rod. If there's no free play at the top of the stroke and the clutch slips, shorten the rod.

[adivin]

One thing I should mention is that the engine is out of the car.  I was trying to make some baseline adjustments now.  So, I don't have the advantage of trial and error.

[Mark Maras]

Adjust the rod length so there's about 1/16" of movement before it starts pushing on the lever. You'll be close.