Clutch slave cylinder

[Wally]

Clutch cylinder is leaking as in image. Its brand new. any ideas what could be cause. I am 99% sure its installed properly? 

I am fine with buying another and putting it on if it will fix the issue? It starts leaking and pouring out when i pump the clutch. cant even 

keep enough fluid in line to attempt to bleed line.

 

btw. i have been absent a couple months. I have my car somewhat running finally. i will post later in mechanical on current engine issues. thanks to everyone who has been super helpful.

Edited January 14, 2022 by Wally

[Zed Head]

I've had a brand new slave cylinder leak.  Sometimes you'll find machining grit inside if you take them apart, even brand new.  Quality control on aftermarket parts is just poor.  Take it back and see if you can exchange for a different brand, then take it apart at home and clean it up inside before installing.

I think that EuroDat has seen similar if you want to search for past posts about it.  @EuroDat

[siteunseen]

"3. Slave cylinder: If it leaks replace it. If you buy a new one, strip it apart and clean it before installing it. The new units often have metal shavings left over from manufacture and that can destroy the new seals."

 

 

[Jeff G 78]

Same as Zed.  I've gotten many bad ones and now I always disassemble them before installation to make sure they don't have any pitting from corrosion.  There is no point in installing a freshly remanufactured slave with any pitting.  It will leak and chew up the new seals immediately.  If the bore looks good on my old failed slave, I just buy the rebuild kit from Rockauto (if they still offer) for a few bucks.  I've brought back some nasty looking slaves and brake calipers with a Scotchbrite pad and brake clean.

[Wally]

roger that. i ordered a new one. When it arrives i will take it apart and post images just to see what ya'll think. 

[EuroDat]

On 1/14/2022 at 9:19 PM, Zed Head said:

I've had a brand new slave cylinder leak.  Sometimes you'll find machining grit inside if you take them apart, even brand new.  Quality control on aftermarket parts is just poor.  Take it back and see if you can exchange for a different brand, then take it apart at home and clean it up inside before installing.

I think that EuroDat has seen similar if you want to search for past posts about it.  @EuroDat

Yes, totally agree with @Zed Head The quality of these after market parts is low, as is the assembly of said parts. It sounds like they damaged the piston cup seal during assembly. Whether the cup seal lip caught on the side during assembly or machine sworth damaged it you will only know by dismantling it.

If you take it back for another, make sure you dismantle the new one and clean it properly before use. Ask them for some grease suitable for EPDM rubber, it is usually red in color, to lubricate the seal when assembling.

You are using a spring on the fork. Is the slave cilinder for the 240Z or the later 280Z version. You can't use a spring on the later 280Z versions because they have and internal spring and the two springs work against each other. You can use the adjustable fork with the later 280Z version, just needs a little attention on how to adjust it properly.

[Dave WM]

i bought a new one from nissan, not a lot of money, I like to get OE parts where possible. 

opps did not notice the spring, my 280z that I was able to get the slave did not have one. Maybe 240z slave in NLA from nissan. 

Edited January 17, 2022 by Dave WM

[Wally]

On 1/16/2022 at 6:16 AM, EuroDat said:

Yes, totally agree with @Zed Head The quality of these after market parts is low, as is the assembly of said parts. It sounds like they damaged the piston cup seal during assembly. Whether the cup seal lip caught on the side during assembly or machine sworth damaged it you will only know by dismantling it.

If you take it back for another, make sure you dismantle the new one and clean it properly before use. Ask them for some grease suitable for EPDM rubber, it is usually red in color, to lubricate the seal when assembling.

You are using a spring on the fork. Is the slave cilinder for the 240Z or the later 280Z version. You can't use a spring on the later 280Z versions because they have and internal spring and the two springs work against each other. You can use the adjustable fork with the later 280Z version, just needs a little attention on how to adjust it properly.

its for my 71 240z. the clutch fork did have the spring attached btw. 

[EuroDat]

5 hours ago, Wally said:

its for my 71 240z. the clutch fork did have the spring attached btw. 

You shouldn't be using the external spring with that slave cylinder.

They changed the slave cylinder design in the 73 model 240Z. Up to 73 they used a external return spring. In 73 they went to a internal spring (in the slave cylinder) and it didn't require any adjustment during the life of the clutch disc.

How to adjust it?

Adjust the push rod until all free play is gone. Then screw the ball headed nut another two turns. Lock it with the lock nut.

Check it by pushing the clutch fork into the slave cylinder. It should push about 10 to 12mm. When you let it go it should return and have no free play.

Another thing. You will most probably have to shorten the push rod or cut more thread to get to a range suitable for the slave cylinder.

If you want to keep the external spring do this. Make a plate out of 2mm steel to fit behind the slave cylinder mounting bolts. Bend it at 90 degrees directly behind the slave cylinder. The spring can connect to this bracket. I have a drawing if you want to do this.

Once you have done that dismantle the slave cylinder and remove the internal spring. It will now work like the early version.

Edited January 17, 2022 by EuroDat

[Wally]

13 minutes ago, EuroDat said:

You shouldn't be using the external spring with that slave cylinder.

They changed the slave cylinder design in the 73 model 240Z. Up to 73 they used a external return spring. In 73 they went to a internal spring (in the slave cylinder) and it didn't require any adjustment during the life of the clutch disc.

How to adjust it?

Adjust the push rod until all free play is gone. Then screw the ball headed nut another two turns. Lock it with the lock nut.

Check it by pushing the clutch fork into the slave cylinder. It should push about 10 to 12mm. When you let it go it should return and have no free play.

Another thing. You will most probably have to shorten the push rod or cut more thread to get to a range suitable for the slave cylinder.

Another thing part II: If you want to keep the external spring do this. Make a plate out of 2mm steel to fit behind the slave cylinder mounting bolts. Bend it at 90 degrees directly behind the slave cylinder. The spring can connect to this bracket. I have a drawing if you want to do this.

Once you have done that dismantle the slave cylinder and remove the internal spring. It will now work like the early version.

thanks for the detailed instructions. They are so clear i think even i can do it 🙂  Had NO idea the spring should be used. it was on the car when i got it....so i just assumed.....

[EuroDat]

Your setup is now a little different from the original setup. You have a 71 clutch fork with the later version slave cylinder. I would remove the external spring and adjust it like I described above.

 

[Wally]

just got new clutch cylinder in. I dont see any pitting marks, so it should be good. This one looks different than my other. 

this has on inside a round black cap inset. its right below rod in image attached. i am supposed to take that out or leave it?

my other one doesnt have that.