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View Full Version : which master cylinder to use in a first gen?



crushed
06-13-2005, 01:48 PM
Are all the IT-7 legal first gen brake master cylinders the same diameter? Which one has the best feel?

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Russ Marshall
#31 IT-7

Speed Raycer
06-13-2005, 02:13 PM
not an answer to your question, but beware of the 79/80 thread pitch... different from the 81 up cars



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Scott Rhea
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jake7140
06-13-2005, 04:51 PM
Originally posted by crushed:
Are all the IT-7 legal first gen brake master cylinders the same diameter? Which one has the best feel?


Can't speak to diameters, but MCs are different (proportioning) between drum brake and disc brake rear ends, so you need to have the correct one. And the thread pitch as noted in the prev post. I prefer non-boosted brake feel, though my current car has power. Good, COMPLETE (see archives for discussion on bleeding methods and why using the brake pedal for bleeding can leave some air in the system) bleeding and pads could also "improve" feel.

Not being a rules nerd, I am assuming you can only run stock MCs with the option of a proportioning valve.

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Steve
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dyoungre
06-15-2005, 10:21 PM
BEWARE !!! Not only did the pitch change, but the mounting holes changed as well, and the 81-? master cylinder does not fit on a 79-80 body. I found this out 2 nights before my first race, the hard way ...

However, many years (and many beers) later, I don't recall just what it would take to do the conversion. I do know that we decided to backtrack and put the '80 back on, even though I had converted from drum to disk. It's never been a problem, as I added a proportioning valve to the back lines ...

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Dave Youngren
NER ITA RX7 #61