I'm planning to put a 10.3" rotors and front Legend calipers on my 90 EF Si.
I would like to keep my 13/16" master cylinder if possible.
So, in fact, I'm just swapping front calipers for a Legend ones (one-cylinder calipers), and was wondering if it would work with my stock 13/16 master cylinder and booster.
Thanks

 

Based off of the fact the 90-91 Ex sedan uses a 15/16" MC with bigger-piston calipers than the other USDM EFs, and that the Legend calipers are bigger than those even, you will get alot of pedal travel before there is enough fluid for you to safely stop the car (maybe 2 pumps of the pedal)

I would just get the 15/16" MC IMHO. Its not expensive (unless you're broke) and easy to change.

 

I have a 15/16" master cylinder at home (t's from the 1990 civic EX), but how to explain, it doesn't match up to my brake booster (two bolt holes on master cylinder are rotated by the 90° angle to two bolts on the brake booster). Need to figure out how to put it on the booster, and will the master cylinder shaft fit in the booster etc...will try to make some pics....

 

A lot of times when swapping the MC, the corresponding booster needs to be swapped too.

 

My bad, I bought a used master cylinder from USA, but thought that I could fit it to my booster...need to think what to do...

 

and what about calipers? Do they fit or you must make something to fit ?