brake trouble

[JBFarmsCummins]

I was driving today and all of the sudden i pressed my brake pedal and it was hard to move and the truck stopped really slowly. I am not very familiar with the hydroboost system on these trucks so i was just seeing what came to mind is the problem.

 

[K204DR]

p/s fluid level ok? hydroboost either works or it don't. any leaks anywhere? if your p/s still works then the hydroboost may have crapped out.