Clutch Master Cylinder Replacement -
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Unread 07-27-2009, 06:26 PM   #1
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1994 YJ Wrangler 
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Clutch Master Cylinder Replacement

Well, the wrecker just dropped me off at home.

I've taken the assembly off the firewall, but I've no idea how/what kind of "nut"/connector is holding the tubing to the unit... any ideas?

Also, any idea on how to bleed the system?

I think this is WHERE, but I've no idea HOW...

THANKS! I appreciate the help more than you know.

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Unread 07-27-2009, 08:06 PM   #2
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This is probably one of the first problems I had with my YJ. The only way you can fix it (that I found) was to go to auto zone and purchase the complete master cylinder assembly. cost me about 150 i believe. It was extremely easy to install. You don't need to bleed the system at all because it is all self contained. Just disconnect the part from the transmittion (you had a picture of it)...and follow the hose and disconnect the other part from the firewall. It will all come out as a single unit, and just put the new one in it's place. Took about a half hour once I figured out what I was doing. You should look into buying a repair manual...they explain everything.
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Unread 07-27-2009, 09:39 PM   #3
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I found there's an allen screw-head on top of the Slave, and tried loosening it to bleed, but NOTHING comes out. It does seem to drive just fine.

I do have a HAYNES manual, but it's not very helpful. It described there being a nut to loosen on the slave to be able bleed using a hose and clear container, etc... not the case.

It seems to be driving fine now even though I haven't bled the system. I hope everything's cool tomorrow on my way to work!

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Unread 07-27-2009, 10:00 PM   #4
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As previously suggested, replace the Master and Slave as an entire unit. They can be bought as an entire assembly, pre-filled and pre-bled, ready to go. The issue with replacing just the master, is that when the master goes bad, it usually transmits debris downstream to the slave, which in turn takes it out. The life expectancy for both the master and slave is identical. So if one goes, the other isn't far behind. To answer your question, there is a roll pin that connects the hydraulic line to the master, you can punch this pin through, and it will release the line from the master cylinder.
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Unread 07-27-2009, 11:26 PM   #5
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The entire pre-bled system is the preferred way to go, for those lucky enough to have that option ('94-'95 owners & converted earlier models) but if you are doing just the master, here is my write-up. This write-up is on an earlier model that uses a flare fitting to attach the hose to the master, but the roll pin type that you have is discussed farther down in the thread.

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No one here knows what they are talking about. You should try Pirate 4x4 they will be happy to help you.

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Unread 07-28-2009, 06:27 AM   #6
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When I replaced my clutch MC, I just installed the new MC, filled the reservoir with fluid and pumped the clutch pedal (by hand at first) until the pressure returned to the clutch.
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