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lorenzo

Can't bleed my clutch 1976 280z coupe

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Okay I am going a little bonkers trying to figure this out. I replaced the Master and Slave cylinder, bled the clutch via the slave cylinder's bleed valve with the two person method and I am still not getting good pressure. Putting the car into gear when parked and running is difficult and putting it into rear gear causes grinding. Any ideas? How would I know if the slave or master could be creating the problem on this specific vehicle?

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Are these new parts?  Rebuilt?  Was anything else done?  Have you checked the slave cylinder boot to see if there's a leak? Did the old parts work?  Why'd you replace them?  Lots of detail missing.

 

Have someone watch the slave cylinder rod and clutch fork while you push the pedal, or vice-versa.

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Are these new parts?  Rebuilt?  Was anything else done?  Have you checked the slave cylinder boot to see if there's a leak? Did the old parts work?  Why'd you replace them?  Lots of detail missing.

 

Have someone watch the slave cylinder rod and clutch fork while you push the pedal, or vice-versa.

 

Yes they are new parts, even replaced the rubber pressure hose that attaches to slave cylinder. I have looked for leaks and don't see any. I replaced awhile back because at the time my stick was very wiggly and I thought replacing the master and slave would solve the issue, turned out I needed to replace the plastic boot at the bottom of the stick which I have done and it is now nice and tight.

 

The fork moves back and forth when I get some pressure in the system. 

 

If I remember correctly the clutch pedal should be fairly tight when pushing down, mine feels spongy and lacks pressure. 

Edited by lorenzo

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The fork moves back and forth when I get some pressure in the system. 

How far?  Details.

 

You might try raising the front or back of the car to make sure the bleed screw is at the highest point.  The bubble can sit at the high spot while fluid goes out the bleeder.

 

It's a simple system, but small details can get you.  Like I said did you check the slave cylinder boot and you said that you "checked for leaks".  Might not be thorough enough.  You have to remove the boot to know if the cylinder is leaking, the fluid will stay inside.  So a glance at it by eye won't do it.

 

Might take some thought and study to understand.  If you replaced the clutch parts because your shift lever was wiggly, there's much to learn.

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I feel your pain!

 

I fought the same battle when I replaced my master and slave cylinder. I tried bleeding in the conventional method countless times and could not get a good pedal. I am 99 percent sure that you have air stuck in the system. The air does not want to naturally go downhill when bleeding.

 

Try this: it works amazingly well!! Reverse bleeding with a standard oil can. I used this method one time and got a perfect pedal!

 

Check it out:

Edited by gdv350ss

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Did you bench bleed the clutch master? If you did not, there is a lot of air in the master that is difficult to bleed out through the long hose and slave. As a diagnostic procedure, remove the fill cap from the master and then remove the filter screen from the bottom of hte fluid reservior (if it is in there). Now you should be able to see the fluid transfer port at the bottom of the reservior. Have a helper press the clucth pedal slowly while you watch the fluid in the reservoir. Normal operation should produce a small squirt of fluid up from the master that shoots up toward (and perhaps past) the surface of the fluid (be carefull as this could get brake fluid on the firewall or fender). If there is air in the master cylinder you will see air bubbles come out from the port. If you see air here you have to bench bleed the master. You can do this in the car by loosing the nut that hold the steel line in, or there may be a bleeder valve next to the line fitting. Eitehr way, bleed the master before proceeding to the slave.

 

Did the clutch ever work since you got this car? Did you or the previous owner put in a new clutch or (more importantly) pressure plate? The lenght of the collar that holds the throwout bearing must be the correct length to work with the pressure plate you have. This is a common pitfall with this car. Even the kits that include the collar get it wrong sometimes.

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I feel your pain!

 

I fought the same battle when I replaced my master and slave cylinder. I tried bleeding in the conventional method countless times and could not get a good pedal. I am 99 percent sure that you have air stuck in the system. The air does not want to naturally go downhill when bleeding.

 

Try this: it works amazingly well!! Reverse bleeding with a standard oil can. I used this method one time and got a perfect pedal!

 

Check it out:

 

Thanks will try this and adjusting the rod further as suggested by others.

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Did you bench bleed the clutch master? If you did not, there is a lot of air in the master that is difficult to bleed out through the long hose and slave. As a diagnostic procedure, remove the fill cap from the master and then remove the filter screen from the bottom of hte fluid reservior (if it is in there). Now you should be able to see the fluid transfer port at the bottom of the reservior. Have a helper press the clucth pedal slowly while you watch the fluid in the reservoir. Normal operation should produce a small squirt of fluid up from the master that shoots up toward (and perhaps past) the surface of the fluid (be carefull as this could get brake fluid on the firewall or fender). If there is air in the master cylinder you will see air bubbles come out from the port. If you see air here you have to bench bleed the master. You can do this in the car by loosing the nut that hold the steel line in, or there may be a bleeder valve next to the line fitting. Eitehr way, bleed the master before proceeding to the slave.

 

Did the clutch ever work since you got this car? Did you or the previous owner put in a new clutch or (more importantly) pressure plate? The lenght of the collar that holds the throwout bearing must be the correct length to work with the pressure plate you have. This is a common pitfall with this car. Even the kits that include the collar get it wrong sometimes.

 

Thank you great post will try this if above simpler techniques do not work.

 

No unfortunately I was not aware at the time I did it that it would be that important to bench bleed with this car. 

 

Clutch and car drove worked well yes. Clutch has maybe 5000 miles on it?

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I had a hard time removing the air from a new clutch master cylinder from Auto Zone Part # 11795 on a 1977 280Z. To start with the new push rod was 1/2" shorter then the original. I replaced the rod with the one from the original, set at 5" from bolt seat of cylinder to Ajuster pin hole center, same length as it was when removed. 
 I had the play needed at the top of peddle but it appeared to me that the peddle was bottoming out before the cylinder was fully depressed. So I turned the ajuster almost all the way out to assure the cylinder was being fully depressed. That solve the bleeding problem for me. I then adjusted the push rod to a point that every thing worked 
like it should, about 5 1/4" +-. A 20 minute job turned into an eternity.

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I have used an oil can and pumped the fluid up with success, I saw my fork move but still had problems with the car never getting into gear (always neutral). It turned out to be that I used the wrong throw out bearing sleeve. If you have driven your car and not have Issue I would assume this is not the case, but to check you can unbolt your slave cylinder and try to move the fork by hand. There should be some play. Mine had zero play meaning the clutch was always engaged. Had to pull the tranny off and and replace with the correct model for the clutch as the clutch determines the throw out bearing sleeve. I had a 240z clutch and was using a 280z sleeve. I ended up buying a 280zx turbo clutch and throw out sleeve and now my car drives great.

 

Just a thought, probably not the issue.

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