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I replaced the clutch master cylinder last Friday and it turned out to be an all-day project. I ended up changing it out with THREE different master cylinders. I could not get any of them to give me a full pedal. The three new master cylinders didn’t seem to be as well built as the old one. I even thought of re-building the old one, but couldn’t get the piston out. Any thoughts on a good replacement master cylinder. Driving without a clutch is a bitch.

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76 LUV

Did you bleed the slave cylinder?

Yes. I ended up using two 2 pints of brake fluid.

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76 LUV

I don't recall ever having that much trouble replacing master or slave cylinders. I usually can even get away without bleeding the slave. I get the hose fitting to the slave loose, pull the slave off the trans so it hangs vertically, fill the master completely, then undo the hose from the slave. Let the dribble of fluid fill the slave up and overflow slightly, then twist it onto the hose fitting and tighten. Just have to be careful not to let the master reservoir run dry.

When doing the master cylinder it can take some bleeding to get the air out of it initially, but a couple pumps with the pipe off of it usually does it.

Like I said, its never given me too much trouble even following the book procedure. You might be right in thinking you are getting some bad parts.

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95 Isuzu Trooper Daily Driver
86 Isuzu Trooper reliable backup
77 LUV 2wd stock beltway blaster (resting)
79 4x4 LUV project: 2.6L, 5spd, 31s (eventually)

MEPR: Man, my 4x4 makes all other LUVs look good

Did you think maybe the slave cylinder was bad too?

Good point. What led to the master cylinder replacement? They always failed with a leak into the cab for me.

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95 Isuzu Trooper Daily Driver
86 Isuzu Trooper reliable backup
77 LUV 2wd stock beltway blaster (resting)
79 4x4 LUV project: 2.6L, 5spd, 31s (eventually)

MEPR: Man, my 4x4 makes all other LUVs look good

Usually when a master cylinder for a clutch goes bad the slave is bad too.That is why most mechanics will tell you to replace them in pairs.

It was leaking into cab. Everything was fine before replacement.

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76 LUV

I thought the same thing.But I wound up replacing both 5 miles after the clutch master.It just won't hold up with all the new pressure.

Do you have free play in the pedal?

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Certified pilots, looking down on people since 1903.

Yes. More then I would like. I push down about two inches before I feel any resistance.

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76 LUV

What I am saying is the rod from the pedal needs to have some free play before it contacts the master cylinder moves.

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Certified pilots, looking down on people since 1903.

When I swapped the diesel running gear into mine, I had to change things around a bit with the slave cylinder so I swapped out the stock master cylinder for a matching Wilwood unit. It fit the stock mounting holes and all I did was switch over the linkage for the plunger. Worked well. Details are in my build thread in my signature.

Hope this helps,
Eric Q.

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'75 body with '82 diesel running gear
My build thread.