I have a 96 4runner. I have noticed that sometimes the brakes seem to get gunked up or something when I'm off-roading. It feels like the front discs get a film on them or something and I have to pump the brake a few times to clear them up. It makes kind of a grinding noise if I push down with out pumping, and the brakes don't really work till I have pumped them. I really noticed it this weekend driving around in the mud and rain, but I have also noticed in dry conditions with a lot of dust. Once it even happened on the road with just rain.
I know something is not right, I took it in to a shop and described the problem and they did not know what it was. If anyone has any ideas they would be much apprciated.

 

My breaks acted like that after off roadin in the mud once and they just cleaned themselves after staying on the road for a while. I thik you are suposed to try and spray out your breakes ofter you go off roading in nasty condions.

 

Just spray with water? Or something else?