master cylinder - tiny metal piece - what is it, how is it held in place?

[lamelylounges]

hi folks,

rebuilding my front brake master cylinder.

as I was cleaning, this little doodad fell out.
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i can see 2 holes at the bottom of my master cylinder - a tiny air hole and a bigger fluid hole.

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1 - i assume i just press this little metal doodad into place
2 - is that enough to hold it in place???
3 - what is the purpose of that thing?

thanks!

[Captain 80s]

Yes, just press it in place. It covers the tiny bleed hole. Without it, a stream of brake fluid will come out during bleeding and get all over everything you don't want it on.

You do it once and you'll never forget it again.

[6]

Yes, just press it in place. It covers the tiny bleed hole. Without it, a stream of brake fluid will come out during bleeding and get all over everythimg you don't want it on.

You do it once and you'll never forget it again.

That's one of those parts that I know is there, I just accept that it's there and never give any thought to what in the hell it's for.

[lamelylounges]

Yes, just press it in place. It covers the tiny bleed hole. Without it, a stream of brake fluid will come out during bleeding and get all over everything you don't want it on.

You do it once and you'll never forget it again.

Ahah.
After rebuilding this time, I don't imagine I will need to do this again anytime soon.

[squirrelman]

it's an eye protector cuz you'll get a shot-squirt to the face without it.

[tian647]

Is DOT 4 good for skin health and complexion? Asking for a friend...

[lamelylounges]

tian647, yeah i don't think so! =

Ugly Before Shots (tho I had already done a little cleaning)

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By the way, it was tough to get out the spring/piston assembly from the master cylinder. i tried using need nose pliers to wiggle and pull it out with no luck.
Then I tried using a screwdriver to lever it out and you can that I busted the top, which fell off shortly after this picture was taken.

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Fellow hawkster, Will T, suggested using some sort of punch to drift it out. I used a dremel to remove the tip from my screwdriver, and then filed and polished it smooth.
To try to be careful of the inside bore of the MC I cut some rubber tubing that went over the shaft.
With some heat and lots of penetrating liquid it finally came out. Very satisfying.

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Happy to report that the MC is reinstalled, topped up with fluid, and even was able to build up pressure in the brake line and squeezing the lever applies force to the calipers.

While I was in the neighborhood I gave my throttle cables and right side switchgear some love. Nice and smooth now.

Next up is the front caliper rebuild.