Fluid Replacement Intervals have changed

[Leafdriver333]

I thought that was the reason for the phantom braking on Autopilot.

Actually, those phantom brakings during AP free trial probably used more pad material on my car than all my brake usages combined since delivery 4 months ago.

 

[A.N. Gineer]

You guys realize the car can't regen down to 0 mph right?

I can't recall ever driving my Tesla without having to use the friction brakes multiple times, even if it's just the last few MPH.

It's the fact you rarely need do it from speed that is why the pads/rotors last so long

You can't drive moisture off with your granny-braking. They need to get hot...

Here's the reason you also can't lube the pistons:

Now, that is a bit exaggerated since the Lambo uses carbon matrix brake rotors, but the reason you stop is kinetic energy (from speed of the car mass; Energy = 0.5mv²) gets converted to heat and dumped into the rotors, as you can see in the video. Double your speed and you need to dump 4x the energy into the brake rotors to stop. So, granny-braking at 6 MPH vs 60MPH and you're dumping only 1% of the heat at 60MPH into the rotors to stop. Moisture then makes the pistons that actuate the brake pads seize in the calipers.

Ride the brakes down Pike's Peak and the rotors get so hot that there's no more heat you can sink into them and you no longer have brakes at all*. Those carbon rotors on the Lambo allow dumping of more heat energy by being able to run a lot hotter than iron rotors.


[optional-reading anecdote about downhill braking follows]

*Which is why there's a Park Ranger roadblock halfway down, taking the temps of your rotors, and making you park the car for 20 minutes, IIRC, before you can keep going down the mountain. I came down super fast, passing a lot of cars, but almost exclusively used engine braking before hitting the roadblock. He laughed and said I could proceed, but that a lot of the pulled over people would get pissed off, so he asked that I park for 10 minutes before proceeding. Most of the long haul bus drivers in places like Thailand ride the brakes down the hills in mountains, then the brakes get so hot, they have none and then dson't make it around a curve, killing dozens of people -- the reason for the accident is always cited as "brake failure" making the driver blameless because he (it's always a he there) filed the police report describing that the brakes stopped working. How much will this carnage change as regen becomes ubiquitous in buses?

 

[25firedog]

Just downloaded the May 16, 2019 version of the manual. Last one I'd downloaded was November 12, 2018.

Brakes are now check every 2 years, replace if necessary.

Battery coolant should now last life of the car.


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Well the heat in South Florida is not your friend. Ambient temperature above 90* F the road will exceed 145*F. Doubt coolant for batteries will "be effective" for that timeline. I do hear battery coolant pump on hot days like today...97* F today. Interior was 121*F before turning on AC.

Part 2 brake fluid is hydroscopic. Will absorb water from the air. Leading to internal corrosion and seals breaking down. 70% humidity in South Florida is a good day. Many days it is 90% or higher. Even if regen extends brake pad/rotor life, brake fluid needs changing or risk brake system problems! Every region needs master mechanics on their teams. Manuals are guides.

 

[Daniel in SD]

Well the heat in South Florida is not your friend. Ambient temperature above 90* F the road will exceed 145*F. Doubt coolant for batteries will "be effective" for that timeline. I do hear battery coolant pump on hot days like today...97* F today. Interior was 121*F before turning on AC.

Part 2 brake fluid is hydroscopic. Will absorb water from the air. Leading to internal corrosion and seals breaking down. 70% humidity in South Florida is a good day. Many days it is 90% or higher. Even if regen extends brake pad/rotor life, brake fluid needs changing or risk brake system problems! Every region needs master mechanics on their teams. Manuals are guides.

ICE vehicles coolant change interval is 100K+ miles and the coolant runs at 180F+. If your battery is running that hot then you can just do the coolant change when you have to replace your battery in a couple years
Brake fluid change intervals will change depending on climate, not everyone lives in a swamp

 

[Atari2600]

*Which is why there's a Park Ranger roadblock halfway down, taking the temps of your rotors, and making you park the car for 20 minutes, IIRC, before you can keep going down the mountain. I came down super fast, passing a lot of cars, but almost exclusively used engine braking before hitting the roadblock. He laughed and said I could proceed, but that a lot of the pulled over people would get pissed off, so he asked that I park for 10 minutes before proceeding.

I would have insisted on not waiting just to give ICE owners one more thing to consider.

 

[DrDabbles]

If what you say is true then could preventive maintenance simply be periodic lubrication of the pistons ?

This is literally an item on Tesla's maintenance list. They suggest having a brake lubrication service done every winter season, so if you live where salt is used, you should plan on that. Getting it done at the same time you get tires rotated or swapped over for winters is pretty easy.

Road salt will destroy pistons and calipers regardless of brake usage though. So the "lifetime" brake claim is at best an uninformed statement from a person living in a climate that doesn't exist in 60% of the US.

My car spent 30 days in a body shop. They moved it around a bit during that time but on the last day they went to back it up and a rear pad was frozen to the rotor and it literally broke the pad and fell out to the ground. 4,400 miles on the odo. Performance model.

Pads can crack and fall apart with calendar age rather than mileage age, too. The binders start to break down as water penetrates and isn't driven off by heat. Combine that with freeze/thaw cycles and it's a perfect recipe for finding out your pads are dangerous at the least convenient time.

Everybody should get them inspected annually by a reputable shop. Just because they don't respect their life doesn't mean they should endanger everybody else's.

 

[Magnets!]

Pads can crack and fall apart with calendar age rather than mileage age, too. The binders start to break down as water penetrates and isn't driven off by heat. Combine that with freeze/thaw cycles and it's a perfect recipe for finding out your pads are dangerous at the least convenient time.

My car is less than six months old and has never been in freezing temps.