MC relief hole / spooge hole

[bochnak]

Rebuilding a front master due to fluid turning to crud.

The MC has 2 divots, the divot closest to the mirror has a large hole that feeds the piston bore. The other divot does not seem to have any holes. Should this divot have a very small relief hole? Very hard to tell. If so, where does the hole lead to, piston bore?

Thanks.

 

[Shaun Chandler]

I think its just there to releive pressure so the system will equalize. I haven't rebuilt my front master becasue I'm not planning on using it. But I did do my rear and there are two holes. If one becomes plugged it won't operate.

Shaun

 

[bochnak]

I think its just there to releive pressure so the system will equalize. I haven't rebuilt my front master becasue I'm not planning on using it. But I did do my rear and there are two holes. If one becomes plugged it won't operate.

Shaun

Right, they won't release. Do you remember where the hole leads?

 

[kirkn]

There should, indeed, be a tiny tiny return hole in that 2nd smaller divot.

Sometimes a tiny wire can be used to poke it clean, but your best bet is an ordinary sewing needle - they are hardened and come to a very very sharp point.

Good luck with it,

Kirk

 

[Shaun Chandler]

I beleive it should go back into the bore like the other one. Atleast thats how my rear is. I would take a picture and post it but I can't even see it in the bore although I can feel it with my finger.

Like bochnak said carefully clean it with a piece of wire. If you know someone who plays guitar grad and old string of them. They come in handy.

I have this thing ( I call it a commando drill, don't know why but I think thats the actual name for it). Google commando hand drill and you will see what I mean. They are micro drills that go into a pen like handle. You just rotate it by hand often used when cleaning very clogged oxy fuel tips.

Shaun

 

[drewpy]

its for the return fluid, so it vents the other side of the piston cup.
this will stop brakes binding

 

[bochnak]

I was able to clean it out with a #80 drill bit. Hole leads directly into bore.

New MC & caliper seals/kit, fresh fluid & bled, brakes work mint now