I don't drive a Chevy myself, but I do know plenty of places online where a Chevy Silverado driver can go for help with its power booster brakes.
Your first stop should be justanswer.com/chevy, a site dedicated to Chevy repair advice, where a similar question to yours has been answered by a professional mechanic.
Try gmtruckclub.com or chevroletforum.com/forum for specific Chevy advice, or fixya.com or 2carpros.com, which are more general car repair communities.
Perhaps you want to go it alone, but you're missing the repair manual you need for the job?
If so, go to assets.gm.com/manuals/chevrolet, where you can find old Silverado manuals, or try calameo.com/books, an online collection of car manuals.
Finally, YouTube has a number of filmed repair tutorials, including this one for a breaks inspection of '98 Silverado, which might give you some ideas: