Valvoline DOT 3/4?

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DJ

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So been a good long while since I have been active here but when it comes to automotive fluids there is nobody I trust more than your guys.

2014 Tesla P85, I am putting on braided lines, with fresh pads and rotors, hardware and going to paint calipers while I am at it.

Parts vendor I bought everything else from suggested AC Delco DOT 3 master cylinder is GM and vacuum boost, says they had master cylinder squeaks with DOT4. I bought two bottles of the Valvoline DOT 3/4 before I got this recommendation.

What would you guys do, use the Valvoline DOT 3/4 I have or find the Delco DOT 3? Worst case I create a squeak and live with it till I flush again?

Regenerative braking has lead to low hydraulic brake use and the rotors corroded on the inner surfaces, lesson learned I will make sure to lube the hardware once a year at one of the tire rotations. Fluid was flushed a year ago by Tesla at a mileage based "4year" annual service but the pedal is still soft, hoping the new lines help in this regard. The newer cars equipped with AutoPilot have a different brake booster setup and MUCH firmer pedal but this higher mileage RWD only car was the one in my price range.

Just so nobody gets the wrong idea this is a family hotrod, I have no delusions about saving the world with my 55% coal powered(local grid supply) car. Last car was LS3 powered and this has the torque and response that was lacking. I also feel a lot better short tripping an EV vs. short tripping a LS3 with 8quart sump that never warms up.
 
If the fluid is a Dot 3 & Dot 4 then use it. If it's a Dot 3 or Dot 4 (but not both) then use what's in the manual which I think is a DOT 3 if I remember correctly.

My vehicles called for Dot 3 and I used Amsoil's Dot 3 & Dot 4 rated fluid (One fluid covers both specs) with 0 issues.
 
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Thank you for the speedy replies. Fluid I bought is dual rated 3and4

Apparently the factory fill is DOT3 AC Delco so from what you are saying what I have should be fine.

Apparently there is some history of the master cylinder squeaking with DOT4 which was the cause for mild concern on my part. Car will be exposed to sub-zero temps too if that matters.

Just noticed my signature and location I moved over 7 years ago and only one of the cars in my sig is still around but has been in pieces for years.......
 
DOT3 is less hygroscopic (and cheaper).

If the brakes get relatively little use, as you say, this might be one reason to use it over the DOT 4 which has a higher temperature rating when new and dry but is likely to deteriorate faster.

Use up the stuff you've got, of course, but when renewing maybe go for the straight DOT3
 
Originally Posted by StevieC
If it's a Dot 3 or Dot 4 (but not both) then use what's in the manual which I think is a DOT 3 if I remember correctly.
DOT 4 is completely backwards with DOT 3. Higher quality too!
 
Originally Posted by DJ
Regenerative braking has lead to low hydraulic brake use and the rotors corroded on the inner surfaces


Re-gen definitely cuts down on overall brake wear, but you should still be using your rotors on basically every stop, right?
 
i used to work on electric forklifts and while not the same as a car I understand the certain benefits of the electric propulsion. The battery is always the problem and the power it takes to recharge them. The Telsa is a beautiful car and I'll call it as being in same class an exotic sports car. They are pretty ! [off topic]
 
Originally Posted by CELICA_XX
Originally Posted by DJ
Regenerative braking has lead to low hydraulic brake use and the rotors corroded on the inner surfaces


Re-gen definitely cuts down on overall brake wear, but you should still be using your rotors on basically every stop, right?


The service brakes are there to hold the car in place and to provide the braking regen can't do or once the limit is reached - that's how it works on a Toyota hybrid - and why a Prius has undersized brakes for its size compared to say, a Corolla or Scion.

I'd run a good DOT4 - Valvoline is one, so is Castrol GT LMA and even better would be ATE Type 200, the old Super Blue Racing basically but in DOT-legal color. ATE SL6 is a low viscosity DOT 4 but it's backwards compatible with DOT3/4 fluids. Teslas come with Brembo brakes and I'm sure that will keep the boys in Bergamo happy.

My curiosity is how do you flush brakes on a Tesla - they want you to go back to their stores for service(which I see as a good thing, no dealer or indie hacks touching things they don't know about) but the human-interacting parts of a Tesla are powered by Node.js and lots of CSS. I'm imaging it's like a Prius or any other Toyota hybrid - use the official diagnostics tool(TIS Techstream) or a Toyota-fluent aftermarket one to access the electronically-controlled braking system, disable the system and pull two relays for the ABS/VSC modulator to bleed the fronts the old school way. Then install the two removed relays and use the scan tool to command the ABS/VSC system to push fluid through the rear brakes and then cycle the system to "clear" the accumulator and high pressure feed.
 
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Originally Posted by CELICA_XX
Originally Posted by DJ
Regenerative braking has lead to low hydraulic brake use and the rotors corroded on the inner surfaces


Re-gen definitely cuts down on overall brake wear, but you should still be using your rotors on basically every stop, right?



If I time it right I don't touch the pedal till under 5mph, car also sat on a dealer lot for maybe as much as 8 months before I bought it which may have contributed to the pad hardware seizing up

Originally Posted by CT8
i used to work on electric forklifts and while not the same as a car I understand the certain benefits of the electric propulsion. The battery is always the problem and the power it takes to recharge them. The Telsa is a beautiful car and I'll call it as being in same class an exotic sports car. They are pretty ! [off topic]

Tesla's battery management is really good, uses the AC for cooling if needed, has heaters when needed which do greatly increase winter energy use. Battery/motor warranty is 8 year unlimited mileage on mine so not at any real risk yet. Most reports are that the battery degrades about 5% in the first few years then plateaus which is consistent with what I am seeing. Batteries are actually just a LOT of 18650 cells for the Model S and X Panasonic I believe. P85 has 7104 of them under the floor, arranged in banks to make 400volts.
 
nthach, I plan to use a Motive pressure bleeder, like a pump up weed sprayer that comes with adapter master cylinder caps, friend bought one for his various projects and I am borrowing it, Vendor who sells the brake parts, and was a Tesla tech offers that tool, says it is what Tesla actually uses which is reasonable to believe. He didn't mention any other hoops to jump thru, I will do more research.

Mine is pre-autopilot so brakes are pretty basic GM vacuum assist and there is a vacuum pump, the newer cars with autobraking might be harder to deal with.

I am maybe a little more mechanically experienced than most the 1996 Caprice referenced in my sig, ran 11.5 in the quarter naturally aspirated and 150miles from home NEVER needing a trailer to do so, ABS, AC power seats all intact. If I can swap a ring and pinion and have it stay quiet on a 500hp daily driver I think I can handle brakes on this thing. Not a lot of cars that run that quick at the track also drive 300miles there and back those days.

Considering changing the gearbox oil too, is Dexron VI in a 9.7:1 gear reduction unit, at times they were recommending no drain till a few hundred thousand miles, then later they wanted a 12K mile drain then leave it for a few hundred thousand. I have no idea if mine has ever been changed at 78K miles. It is just a lube oil, no posi or anything.
 
Originally Posted by DJ
nthach, I plan to use a Motive pressure bleeder, like a pump up weed sprayer that comes with adapter master cylinder caps, friend bought one for his various projects and I am borrowing it, Vendor who sells the brake parts, and was a Tesla tech offers that tool, says it is what Tesla actually uses which is reasonable to believe. He didn't mention any other hoops to jump thru, I will do more research.

Mine is pre-autopilot so brakes are pretty basic GM vacuum assist and there is a vacuum pump, the newer cars with autobraking might be harder to deal with.

.

Sounds a lot less complex than a Prius or the Camry/Highlander/RAV4/Lexus hybrids. Even newer cars with pre-collision braking(it was an option on my parent's 2005 LS430) still use a vacuum assist - it's the ABS/ESP module that does the emergency braking.

I'm guessing Tesla is using the ABS/ESP module to perform the brake phasing during regen braking, while Toyota uses a stroke simulator to provide the "feel" of the master cylinder and a extra set of valves/solenoids in the brake modulator to control the brakes. If the system fails, the stroke simulator is disabled and the master cylinder takes over braking for the front wheels. The Toyota/Aisin(Advics) system is a near perfect clone of Mercedes Sensotronic.
 
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Tesla regen is throttle pedal controlled, full lift is full regen, you can reduce it with mild application of throttle is very well modulated even though having it on the throttle sounds weird it is kind of like driving a manual tranny car in a low gear with how you slow from engine braking when you lift.

The Tesla autobrake equipped cars feel very different pedal wise, and hard pedal first thing is a complaint on just the early cars so I THINK they switched away from vacuum.
 
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