I've got a 97 S-10 blazer and get a groaning sound from the brake pedal area whenever the brakes are applied. Got down there to see if anythng is sticking, etc. and I can't see anything. At least as far as the firewall.

A buddy said it might be the brake booster. Is this something that needs to be replaced and if so how hard is it. I am a novice mechanic. I do my own oil changes, filters, etc. so I know my way around tools but how tricky is this?

Or should I be looking elsewhere?