Brake and battery coolant fluid

MsElectric · Nov 7, 2014

Just curious to see what the recommended maintenance interval is for the brake fluid in the Model S. Does that fluid need to be flushed/replace every certain number of miles? How does this pertain to the new electric brake system. Is that all electric but with a hydraulic backup?

It seems other than the brake system and the battery coolant system there are no other fluids to be serviced right? Is the battery coolant fluid ever replaced/changed?

TES-E · Nov 7, 2014

I would think that the single speed gearbox would need to have the oil changed at some point.

EarlyAdopter · Nov 7, 2014

Most brake fluids are hygroscopic, which means they absorb moisture. Over time they get "wet" which significantly reduces their boiling temperature. As such, brake fluid should be changed every two years.

Unless of course Tesla anticipated the potential of people never bringing their cars in for service and went with a non-hygroscopic fluid (rare). Would be interesting to find out.

gavine · Nov 7, 2014

TES-E said:
I would think that the single speed gearbox would need to have the oil changed at some point.

I read somewhere that this fluid needs to be changed every 15 years.

breser · Nov 7, 2014

MsElectric said:
Just curious to see what the recommended maintenance interval is for the brake fluid in the Model S. Does that fluid need to be flushed/replace every certain number of miles? How does this pertain to the new electric brake system. Is that all electric but with a hydraulic backup?

The new electromechanical braking system is still hydraulic, it just replaces the vacuum assist with a electromechanical assist. So yes you still have brake fluid. Tesla recommends that brake fluid be replaced every 2 years/25,000 miles/40,000 km.

Is the battery coolant fluid ever replaced/changed?

Tesla recommends this be replaced 4 years/50,000 miles/80,000 km.

TES-E said:
I would think that the single speed gearbox would need to have the oil changed at some point.

Tesla recommends the transmission fluid be replaced every 12 years/150,000 miles/240,000 km.

Source for all these numbers.

MsElectric · Nov 8, 2014

breser said:
The new electromechanical braking system is still hydraulic, it just replaces the vacuum assist with a electromechanical assist. So yes you still have brake fluid. Tesla recommends that brake fluid be replaced every 2 years/25,000 miles/40,000 km.

Tesla recommends this be replaced 4 years/50,000 miles/80,000 km.

Tesla recommends the transmission fluid be replaced every 12 years/150,000 miles/240,000 km.

Source for all these numbers.

Wow you know what you are talking about

Thanks for such well searched information! So it seems with major Tesla maintenance we are looking at:

+ Brake fluid every 2 years (25K miles)
+ Battery coolant every 4 years (50K miles)
+ Transmission fluid every 12 years (150K miles)

Any other major fluid flushes/changes or other major service items I am missing other than small things like cabin air filter, wipers, etc., ?

So how does Tesla charge for these services? It seems odd they have a fixed yearly service fee when it seems the best thing to do it is to take in every 2 years as that will get you the brake fluid change and the battery coolant fluid change...

jerry33 · Nov 8, 2014

MsElectric said:
+ Transmission fluid every 12 years (150K miles)

I'd be wary of this one unless someone has a lab report on the fluid and how it changed as miles accumulated. If there is exposure to air (from thermal expansion/contraction via some kind of vent) dust will get in and shorten the life significantly. In the Prius, lab analysis indicates that after 40,000 miles there is significant degradation of the PSD fluid. (Toyota has no change interval for the PSD fluid).

dave · Feb 4, 2015

I'm thinking of getting Tesla to do just the brake fluid this year instead of the full inspection (I do my own tires, wiper blades, etc). Has anyone else done this? Do you know what they charge?

apacheguy · Feb 4, 2015

MsElectric said:
Wow you know what you are talking about Thanks for such well searched information! So it seems with major Tesla maintenance we are looking at:

+ Brake fluid every 2 years (25K miles)
+ Battery coolant every 4 years (50K miles)
+ Transmission fluid every 12 years (150K miles)

Any other major fluid flushes/changes or other major service items I am missing other than small things like cabin air filter, wipers, etc., ?

So how does Tesla charge for these services? It seems odd they have a fixed yearly service fee when it seems the best thing to do it is to take in every 2 years as that will get you the brake fluid change and the battery coolant fluid change...

In they grand scheme of things those are probably the minor servicing needs of the MS. And if you pay for service either a la carte or thru a service plan, they're already included. Major service items would be a master charger or touchscreen failure out of warranty. It has happened and, no, owners were definitely not happy to be forking over several grand for a "low maintenance" EV.

SabrToothSqrl · Feb 5, 2015

2 years on brake fluid? I've gone 15 in my last car with only ever topping it off.

scottm · Feb 5, 2015

SabrToothSqrl said:
2 years on brake fluid? I've gone 15 in my last car with only ever topping it off.

Stop much?

muleferg · Feb 5, 2015

From the Tesla Manual

Warning:
Contact Tesla immediately if
you notice any significant or sudden drop
in fluid levels or uneven tire wear.
Fluid Replacement Intervals
Do not change or top up Battery coolant and
brake fluid yourself. Tesla service technicians
replace fluids at the regularly scheduled
service intervals:
• Brake fluid. Every 2 years or 25,000 miles
(40,000 km), whichever comes first.
• Battery coolant. Every 5 years or
62,500 miles (100,000 km), whichever
comes first.
Note:
Any damage from opening the Battery

apacheguy · Feb 5, 2015

muleferg said:
• Brake fluid. Every 2 years or 25,000 miles
(40,000 km), whichever comes first.
• Battery coolant. Every 5 years or
62,500 miles (100,000 km), whichever
comes first.
Note:
Any damage from opening the Battery

Something changed there. I've seen one of the inspection sheets that they use when completing annual service. Battery coolant definitely used to be replaced every 4 or 48,000 miles.

marchyman · Feb 7, 2015

SabrToothSqrl said:
2 years on brake fluid? I've gone 15 in my last car with only ever topping it off.

Brake fluid is hygroscopic. When the absorbed moisture hits about 4% of the total volume the fluid needs to be replaced unless you like the idea of brake fade due to the presence of air bubbles from water boiling out at the high temperatures that can be generated in brake use. How long it takes to hit 4% varies depending upon where you live. 2 years is a safe number. Another choice is to buy one of these (assuming the Tesla uses DOT 4) and change when needed.

ggr · Feb 7, 2015

marchyman said:
Brake fluid is hygroscopic. When the absorbed moisture hits about 4% of the total volume the fluid needs to be replaced unless you like the idea of brake fade due to the presence of air bubbles from water boiling out at the high temperatures that can be generated in brake use. How long it takes to hit 4% varies depending upon where you live. 2 years is a safe number. Another choice is to buy one of these (assuming the Tesla uses DOT 4) and change when needed.

The brakes don't fade, they lock up!

marchyman · Feb 8, 2015

The typical failure mode is the formation of vapor pockets when the fluid gets too hot. The vapor displaces fluid (which can cause lock-up, but not always). Vapor is compressible. When brakes are applied the pedal may go all the way to the floor (compressing the vapor) without applying the brakes! Brakes can also lock up if the water content is enough to cause corrosion of internal parts and left to sit for a while. That is sometimes a cause of expensive ABS unit failures in my motorcycle experience.

SabrToothSqrl · Oct 23, 2017

scottm said:
Stop much?

Only 285,000 miles worth of stopping.

DFibRL8R · Oct 12, 2018

The current Model S manual now says "Battery coolant: Every 8 years or 100,000 miles (160,000 km), whichever comes first." Interesting that the interval recommendation has changed for the better (less maintenance required).

SabrToothSqrl · Oct 12, 2018

lol, that's like BMW telling you, you can go 15,000 on an oil change. Not sure it's for the better... but again I'm not worried 'bout it.

Brake and battery coolant fluid

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