[fragmede]

On a system as critical as the brakes, I highly doubt they yolo just guessed and said, eh, just make it 4 years, that sounds good. I find it far more believable they did extensive testing of the brake system, which they build, and thus know just how much water is and isn't getting into the system, and what a good fluid replacement interval is.

Or maybe everyone that works there is an incompetent monkey and they never test anything, ever. It's probably that, definitely. That's also why we see so many stories in the news about 5 year old Tesla's brakes failing. Given that we all know how long full self driving has been promised, I'm sure we'll get those news stories any day now.

[tristor]

Like anything in safety critical engineering there are margins of safety. Seal failures in the top end of the brake system can cause water ingress without immediate impact on the braking system but will eventually cause hard lines to rust through, causing sudden and catastrophic failure of the braking system.

The hydraulic portion of the braking system in a Tesla is not significantly different than any other passenger car, so yes, it’s utterly incompetent to recommend twice the maintenance interval.

[mantas]

Maybe Tesla is just hyper-focused on Silicon Valley? I could see brakes fluid lasting that long in such a nice climate. In Northern Europe where lower part of the car is in salty water bath for 6 months a year… Checking brake fluid LEVEL every 4 years feels like looking for a trouble.