Monojet MV Part Spec question

[Sixteen Tons]

Rebuilt my Monojet some time back. Taking it apart I noticed that the plunger rod in the vacuum break assembly (part #12 in pic) was missing. I rigged one up during rebuild only to recently find it missing(!) again, only noticed it due to start up/idle changes, apparently not an insignificant part of this carb. So, I have the circular base and the rebuild kit came with a new diaphragm. I would like to replace it properly this time (braise 'em together probably) and was hoping someone with the same carb could give me the length of this small (but necessary) piece. Thanks!