# Need Help: 84 z31 clutch master cylinder



## watagg (Sep 14, 2007)

Hi, I am new and this is my first post. So if this topic has already been addressed, I am sorry. I did not see it. I have an 84 z31 NA. The cap on my clutch master cylinder is cracked. It looks as if the last owner over tightened the cap. My question is; if there is no pressure in the line will the clutch remain engaged or will it just disengage? Also, the cap I have is full threaded, not a 1/4 turn cap. But the caps I found in the junk yard are 1/4 turn. I checked the Nissan genuine parts website and it says that all the years use the same cap. Does this mean my master cylinder has been replaced or were there different caps for GL, GLL, AE, and Turbos? Thanks for any help.


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## Zen31ZR (Mar 24, 2004)

The cap has absolutely nothing to do with the pressure in the clutch line. The pressure is created in the long horizontal part of the master cylinder. The part where the cap is, is nothing but a fluid reservoir and holds no pressure. However, due to the crack in the cap, moisture can get in and contaminate the fluid and rust out your brake calipers and also create a spongey feeling pedal, as the fluid (same as in the brake system) absorbs moisture quickly, and so it should be replaced very soon. 

It's possible you may have a MC from a different car. I don't remember much about what can be modified in that area, unfortunately. You can simply buy the correct stock master cylinder and have it installed. Unless you are very familiar with installing hydraulic clutch components, I would not attempt this yourself.


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## Zen31ZR (Mar 24, 2004)

Also, you can take the cap down to the local auto parts store and try to match it up with anything they may have in stock. That would be cheaper and easier than replacing your entire master cylinder........


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