Master Cylinder Side Bolt (1 Viewer)

[DanStew]

i changed out the original brakes on my 1970 Cruiser.
I am using a 1976 brake master cylinder
When i first installed the setup i put plugs in the bottom to close those circuits and i also unscrewed the side bolt on the MC not knowing what it did. heck still dont know what it does but it kind of felt like it went back as it should. And now i am finally getting the brakes bled to drive, but i still have soft brakes even with the fluid not having bubbles.
My question is what does that side bolt do for the MC? I am thinking I screwed something up and maybe messed up the MC.

Thanks

 

[1911]

My question is what does that side bolt do for the MC? I am thinking I screwed something up and maybe messed up the MC.

Thanks

It fits in a groove in the master cylinder plunger; when installed, it prevents the plunger from either going too far in and bottoming out, or coming out the rear and losing vacuum - I forget which.

 

[DeskJock]

I've attached a picture of what I think is the bolt that you're referring to. the Factory Service Manual refers to it as a bolt. My initial thought is that it retains something. I'm currently in the process of installing @cruiseroutfit booster and Master. I didn't touch that bolt; and, just staring the bleed process.