Hello,
recently I've replaced bother the brake booster and master cylinder on my 1994 Blazer full size. I don't have a press and didn't really get all the air out of the master cylinder but still went on to complete the installation. Shortly after trying to bleed the brakes by pressing the brakes, a loud creaking sound can be heard when pressing the brakes. Sometimes at low speeds the noise is very subtle, but at higher speeds the sound is really loud. The sound seems to be coming from the master cylinder or booster area. I should add that when I ordered the brake booster, the box arrived damaged and Am now beginning to suspect that the brake booster is at fault but I'm only a rookie and seeking help from you guys.