that there master cylinder and doin a thang

[Liamrdv]

So I've come to the issue that my master cylinder will not create any pressure? I do not have a clue what could be going on but even if I remove the hose it doesnt spill any liquid out of the master cylinder, not sure what to do here! Also if I squeeze the brake lever a plume of silvery looking crud will float up out of the little hole in the bottom, only one hole actually does anything out of the two.
The model of my bike is a 1982 XS400J.
Any help would be appreciated! I'm on the verge of tearing the cylinder apart, so I'd be happy with some pointers before I do so.

Side note, I can squeeze the lever back and forth a thousand times, I literally must have done it a thousand times and theres no pressure coming back at all, but the silvery coloured shit keeps floating up in the fluid, gots me no clue, somebody help!
<--- where I'm at... <---- where I wanna be

 

[Lego]

As you said, tear apart and clean the master cylinder, if it will not help, or after tearing it apart you will see that something is broken. rubber parts for example, buy rebuild kit.

 

[rshutchinson]

Skip the rebuild and buy a new one on eBay. There are plenty of styles available. The rebuild kits are more than the cost of a new master. Even after rebuilding the Masters sometimes the bores are too pitted or too big and don't work.

Just what I would do and I have used rebuild kits before as well.

 

[Liamrdv]

Well shit, I should have checked on here before I went to my bike mechanic today, I got him to order me a rebuild kit feeling a bit pressured, oh well though, maybe the next time this comes up I will just buy a whole new set up like you said, just checked ebay and theres pretty well the exact same set up I have on there for half the price of a rebuild kit.

 

[lemonhead]

I cleaned my master and had a heck of a time getting pressure too. Ended up being tiny air bubbles in the ports.

Here's what I started with:

I didn't rebuild the thing either...just cleaned. Took about 3 hours, 20,000 pumps of the lever and a very fine wire poked down the holes to coax the tiny bubbles out. Eventually it built pressure and now, works great.

 

[Liamrdv]

Unreal, thats one nasty looking assembly, and I thought mine was bad, good to hear your perseverance panned out for you in the end, I had mine going that route as well, I pumped it for the better part of the day trying to reverse bleed , regular bleed, shake the bubbles out anything, nothing worked, so I tore mine apart, come to think of it the seals really didnt look that bad, I just felt like 30 year old pieces of rubber were better changed than not i guess.