Conversation Between bmoran4 and NGN 52

Howdy Hi, I have a 52 f8 fire engine with a howe package on it and have been working the last 18 months turning it into a food truck serving wood fired pizza. Now don't get mad I haven't hurt the inegrity of the truck but as I am now getting ready to work it I am having some issues with the brakes. Sometimes the pedal is working and other it is hard as a rock, can still brake but with great effort. In you wise ways and great wisdom can you best direct me on where to check first and how. I am thinking that the power chamber has not had much use over that last decade and thought it might be sticking some. Some times I put on brakes once and all is fine and then apply pressure again and vacuum assist seems to be gone. Any advice would be greatly appreciated. JR