Master cylinder bench bleed

[240zadmire]

Folks!

I’m in the process of evaluating whether to upgrade the 15/16” master cylinder with the 10” boost master from 280zx 1979.  I tried to bench bleed the master cylinder and observed the below behavior. 
notice, I didn’t mount the reservoirs on yet.

 

fill up the cups and it’s very slowly draw in the fluid into the bore and out the F and R outlets.  I tried to tap on the side to see any bubble coming out.  Very little.  I even try to pump the cylinder and seem like just air coming out.  
Fill up the cups and left overnight, the F seem to be able to drain completely.

do I need to mount the reservoirs to help with the gravity to pull in more fluid?

[Zed Head]

Looks used.  Are you trying to find out if it's good?  The larger bore will actually create less pressure.  It's bigger because the ZX's had rear discs.

[240zadmire]

It is used.  I bought the Tokico rebuild kit.  Apparently, a close examine the Tokico and the Nabco, the Nabco is a bout 1mm shorter on both piston.  I think the Tokico pistons block the holes.  That's why no fluid gotten into the bore.

ahh well, probably a remanufactured one probably a better route.

Edited August 29, 2022 by 240zadmire