72' Brake Issues ???

[SlammedBlazerLife]

In my 72' Blazer the brakes make a really bad shreak noise with a vibrating pulse that i can kind of feel when i press the brakes when stopping some times.This brake issue gives me poor braking where its seems its hard to stop. The brake issue seems to be coming from the front but the back brakes might be doing it also. The new brake pads that i have replaced in the front have been used for at least 6 months, so i figured they should be worn in by now or help this problem that i have with the brakes. This issue is of great concern to me reason is i use my Blazer for Rock crawling/4 Wheeling and to have good brakes are critical. I need Advice/help with this issue and or any thoughts or recommendations to fix this brake problem, Thanks