So hydro clutch. I can find no example of it being installed in any 73-95 Chevy van from the factory. Everyone that ever posted a pic thank you for the help. With all the searching I did there are two things that convinced me of this, one was I saw they offered a cable around 90 up and the second was a guy in England on fake book that said his van used the cable. At that point I gave up looking for it. The parts sites will show you a master cylinder and the repair manuals will give an example how to bleed it.

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I started with this, the lower is said to be from 78 and the upper is from my van.

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I took it apart and slapped the clutch pedal on for some measuring.

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I went to the store bought a cheap plastic miter box, plastic sheet and some grease pencils.

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If you look up ticking stick, joggle stick, it is a old method of measuring and copying shapes. This can be useful for interior work where you want to find the shape-curves on the wall of your van.

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You trace around the stick and get your points of interest.

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Lay the pattern and stick down, line the stick to your marks and connect the dots.

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I now have a drawing and start filling in the blanks. It only gives you a 2 dimensional point of view but it helps. I wanted the clutch rod to be straight with the cylinder at the end of travel for no side wear of the piston. I could find the length of the clutch rod and so forth.

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Slightly better pic.

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Slapped this together.

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I ordered some 3x3 aluminum block and made a wedge to line up the master with the rod.

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Seems good?

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Drilled some holes.

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Made it up to here so I could go outside and eyeball things.