Brake Disc Pads problems of the 2008 Lexus LS460

I had remarked to the local dealer that it made a clunk noise when starting the vehicle and depressing the brake pedal. This was at 63k mi when I purchased it. I was told it was normal. Approximately 1 year and 10k mi. After I started to experience squealing when braking. I was told by the dealer that no issues were found and that it was most likely caused by cheap aftermarket brakes. I brought the vehicle in for the brakes again and was told that they found nothing wrong, probably just cheap pads. Approximately 3k mi. Later when driving at approx. 35mph. Warning lights illuminated, and stated to take immediately to the dealer. When I took it I was informed there were codes regarding an electrical malfunction and leak, but they found no evidence of the problem. They reset the car and attempted to re-illuminate the warning lights, which they were unable to do. Approx. 1k mi. Later the warning light re-illuminated. When I spoke to the dealer they asked if I had any driveability, or braking issues, which I did not, the car drove and braked normally. I was told they could look at the codes again and reset them, but they would most likely come back on again if it was some other type of malfunction. I was planning on putting the car away for the winter and addressing the issue then, the dealer agreed that it was most likely the best to bring it in prior to taking it off the road for winter. Once again approx. 1k mi. Later a constant beeping started while driving shortly after a hard braking incident. It stopped, but started again 2 wks later while driving home as I approached an exit ramp. I depressed the brake pedal to find I had no braking ability. Pedal to the floor. I entered the 1/16th of a mile ramp at 65mph. I swiftly downshifted enough that I made the turn at the end t on to my street with only minimal fishtail and found that the vsc was still functioning.