Question on front master cylinder for a '98 EV1100

[maquette]

In the pic attached, what is the purpose of the two small holes at the bottom of the master cylinder? One is smaller than the other and has an even smaller hole down inside of it.



Obviously I know nothing about brakes, but I want to know the purpose of these holes and if they can become plugged?

Thanks in advance.
 

[twodogs]

Don't plug em up, someone will be along that can explain how they work better than I can.

[maquette]

Don't plug em up, someone will be along that can explain how they work better than I can.

I don't want to plug them up, I want to know if they can become plugged up and affect the operation of the master cylinder. 

[Antietam Classic Cycle]

Yes, they can become plugged and not allow brake fluid to be drawn into or returned to the reservoir.

[maquette]

Yes, they can become plugged and not allow brake fluid to be drawn into or returned to the reservoir.

Are they both for flow Charlie, or is one of them a vent?

[Antietam Classic Cycle]

Are they both for flow Charlie, or is one of them a vent?

Not sure. I do know they both need to be unobstructed. 

[maquette]

Not sure. I do know they both need to be unobstructed.

I think I found the answer on a snowmobile board. The bigger hole is the "supply" to the caliper and the smaller hole is the "return". I'll clean them out now and see how everything works.

Thank you as usual!! 

[wirespokes]

Makes me feel better knowing Charlie doesn't completely understand that either. 

It's just a simple pump but I've never figured out why that second small hole is necessary, and that's the one that plugs. When it does, the pressure doesn't release and the brakes stay on. If the linkage is too tight, the piston will block that hole with the same result.

Logically, I'd think the large one is all that's needed.