Help! Brake Issue on an 88 635csi

Has anyone else experienced a bang/banging noise in the brake system when the brake pedal is released? The issue does not happen when I brake gradually, just when I step on the pedal hard, or I depress it to the end of its travel when at a complete stop. After I release the pedal I can feel and hear a bang. Does this have something to do with the brake bomb? Any help would be much appreciated.

The brake bomb is named for its appearance, not any sound it makes. Might be a really badly cracked pedal bracket or it might be really screwed up pads or calipers. Have you taken anything apart to LOOK at it?

Stop driving the car immediately. That sounds dangerous.

I have heard of things like this when a break pad cracks, breaks, or comes loose in the caliper. You should look into this sooner rather than later. Good luck.

The feeling doesn't come from the wheels, I can feel it in the firewall right behind the brake pedal. It almost makes me think that it is something with the brake booster. If I release the pedal gently it doesn't make the noise, however if I release the pedal fast that is when i feel a slight bang in the firewall.

Fixed the Problem!!!!

I just got done replacing the entire front linkage on my car. Once the upper and lower control arms were replaced I got the car aligned and then the issue was GONE! The brakes seem to work better now too, no more slop or banging when I release the pedal!!

Sounds as if your bushings were completely MIA ...