As he wrote:
Lauda explained after the race that this turn left was not the direct result of his defect, instead he willingly steered his car into the wall because he had noticed his brake problems and wanted to stop his McLaren safely this way.
As Lauda braked into the sharp righthander at the end of the Brabham Straight, his McLaren turned sharply left, ending the Austrian's long career in the wall
But - and here comes my point - I never believed him, and I´d like to give a reason for this: In various interviews he stated that he wanted to quit Formula 1. He had tried once before, but came back. He had a challenging offer for 1986 from Bernie Ecclestone with his revolutionary new ultra-flat Brabham. He said after the race (I´ll try to remember it as well as I can) that the qualifying result suited him well, since this bad result was a perfect way to get off F1 without much grief. But when he lead the race a few laps from the end he thought "Oh no, I like driving again." So when his defect came, this "was OK by him", because it was the way he was able to quit.
Combined with the strange way it looked (never saw anything else like this), I got the strong suspicion that he never really had a brake defect. He just drove his car safely into the wall to be able to get out of F1 (and, recalling what happened to poor Elio de Angelis in the flat Brabham, maybe this was not bad for him at all).
I´d just like to know if anyone else remembers and thought the same thing, has an opinion on this or has clue to prove or disprove it.