I tried to bleed my brakes the other day and not a drop came out. I brought it in thinking something was weird and they told me that there was contamination of the brake fluid. They think that somehow Power Steering fluid or oil got in there, which causes the seals in the brake line to swell and deteriorate.
I've looked around on the web and done some calling around, I can't get a great answer as to how little is actually little enough, nor to how long a very small amount will take to do this. I did find that a 5% power steering fluid will cause enough swelling within a couple days, and a higher percentage will do it slightly quicker. I'm not sure about the amount to 'top off' the brakes if the wrong fluid was used. The initial mechanic and the dealership say that it could take a few weeks or months to cause enough swelling like this. The brake shop that i went to a few months ago is trying to say that since i have a lot of mileage since going there that it now is magically not their fault - regardless of the fact that I brake less with all the highway miles... anyways I digress. Before the owner got in, it was plausible to them. Whatever. That's the argument I'm still in the middle of.
Anyways, the first place that diagnosed and the dealership suggest replacing most of the brake system - all rubber parts including seals and hoses as they have all likely swelled or are at least contaminated and could recontaminate new parts. Again, I'm not sure where the 'cut-off' point is for that, sorry I wish i had more info. Since I had ABS there is a very expensive module that goes with that, without it repairs were looking around US$1800, with that part another grand on top of that.
Some sites are suggesting that if it is a smaller amount that you might be able to get away with just the master cylinder, which is probably about $100-200 or so to replace. If it got into more than that, then you would likely need to do the whole kit and kaboodle.
Before bleeding the brakes or replacing anything, you would want to get a new turkey baster (to avoid more contamination) and suck out the power steering fluid that should have risen to the top as it should rise above brake fluid and hopefully just be in the reservoir and if you are having issues it probalby got some into the master cylinder. Dispose of the baster after use as it is not good for gravy That way, a normal bleeding afterwards should have less or none of the contaminant, reducing the chance for ruining more seals further down in the calipers and stuff.