RB20 Trans Clutch Engagement Issue

[z-ya]

I'm having an issue with the clutch engaging on my swap. Here are the details:

 

RB25DE

RB20 Trans, clutch fork, bearing collar

RB25 Flywheel

Z32 clutch, bearing, pilot bushing (new)

240SX slave cylinder and push rod (new)

240Z clutch master cylinder

 

Clutch forks moves about 3/8", but the clutch never engages to the point where I can turn the driveshaft when in gear. In neutral I can turn the driveshaft. The driveshaft turns with the clutch pedal to the floor, in gear, and turning the engine at the crank pulley.

 

Any ideas?

[fast-datsun]

Need about 1" of movement to work, bleed to see what that does.

[z-ya]

There is no air in the system. The pedal is firm, and pressure is even throughout its travel.

 

I did a bit more research on this.

 

As we know, the RB20 transmissions is the same on the inside as the 240SX. So I looked up the diameter of the master cylinder and it is the same as the 240z (5/8"). There are two different slave cylinders depending on years, 11/16" and 3/4". I need to measure the on on the car.

 

Pete

[timbo1jz]

did you put the clutch disk in backwards? had the exact same symptoms with my rb20 when I did that.

[z-ya]

I'm pretty sure the disc is in correctly. Otherwise it would not sit flat against the flywheel. Looks like I will have to pull the motor and trans. Even if I use a prykbar to move the clutch fork more than an inch, it still doesn't engage.

[datsun dave]

Change the slave for one with a longer push rod.

[streeteg]

The clutch doesnt engage? or the clutch doesnt disengage? I just had an issue where my clutch didnt disengage. I switched my collar for an SR collar, then cut my floor block plate and was able to get the travel I needed for disengagement.

[z-ya]

Depends on how you look at it. When I say engage the clutch, I mean disengage the engine from the transmission. If I were disengaging the clutch, I would be engaging the engine to the transmission.

 

I did a quick rebuild on the slave I got with the trans (11/16), and tried it. Still no luck. The one I had in there before was a 3/4".

 

Correct me if I'm wrong. If the master and slave are the same diameter, the distance the slave piston moves will be the same as the master. If the slave piston is larger, it will move less than the master, but with less effort. I'm seeing less movement with the smaller (11/16) slave, so I must still ahve air in the system.

 

But why when I move the clutch fork over an inch with a pry bar is the transmission still engaged with the engine?

[z-ya]

So I bled the system again following some suggestions that I found on NicoClub. Held the pedal to the floor, then cracked the bleeder valve. Then I pushed the pushrod all the way in while the bleeder was cracked open. Closed the bleeder while the push rod was all the way in. The Pedal then seemed firmer.

 

So I'm not sure of any of that did anything, because I ended up just putting a pipe wrench on the driveshaft to try and turn it, and it broke free. Now I can turn the driveshaft easily with my hand. Mabe the disc was stuck to the flywheel? I cleaned the disc and flywheel with brake cleaner before putting it all together.

 

Anyway, the clutch works now!

 

Thanks for the suggestions.

 

Pete