I read a recent post by DeanJohns and I saw this other older post that claims a Master Lexus tech said that it would not be total brake failure if the master Cylinder failed, but a much harder force would be required to stop.

It is of course from a technician who has never experienced the event first hand, but he is a Master Tech
https://www.clublexus.com/forums/sc4...l#post10537020

 

We have had multiple reports of total brake failure, however, witness testimony is not very reliable. Have we heard of any cases where a formal "failure analysis" has confirmed a "total brake failure" yet? Anyone?

The thread that sparked this post reported a dealer had inspected for a booster/accumulator noise and said as long as there wasn't a leak, one could live with it. This confirms the early threads/reports of the external brake fluid leak that corrodes the booster pump terminals. However, as most agree, a booster failure will not lead to total brake failure. My guess is most of the total brake failure cases are more likely a boost failure, which can seem like a total failure, especially in the event of an emergency stop in our 2-ton vehicles!

I had a hard time switching from my lightweight '85 MR2 with its short stopping distances, to the longish stopping distances of my heavyweight SC430! As I reported before, I almost rear-ended someone during a panic stop. I was certain something was wrong with the brakes, but it hasn't happened since. I bought lightweight racing wheels to replace the heavy, chrome, G-spider wheels, and stopping distances have improved.