Which DOT 4 brake fluid is best?

Our question of the week this week is about Brake Fluid. What is the best DOT 4 brake fluid, and how often should you change it?
Although though there are some cars that come with DOT 4 brake fluid from the factory, most cars come with DOT 3. Subaru's come with DOT 3 fluid across the board, so if you want to improve the capacity of your brakes, and especially if you want to take your car to the track, you are going to need to replace that DOT 3 brake fluid with DOT 4 which will have a higher heat capacity.
But are all DOT 4 brake fluids the same?
And is there anything that you should keep in mind about change interval, etc when you make that change?
We cover all of this and more in this video.
Thanks for watching and Stay Tuned!
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[@not12listen]

Thank you for making this highly overlooked topic very easy to digest & understand. I am especially happy that you gave a reasonable time frame as per when to service/replace the brake fluid - 1-2 years. I do wish that people would take that 1 specific detail more seriously on their daily driven vehicles. I will absolutely be sharing this far and wide!

[@FlatironsTuning]

Very cool! Thanks for watching, and really glad to hear that it was helpful! Stay Tuned!

[@Gustinpham]

Amazing video, I feel more prepared for my first track day next month! Thank you

[@FlatironsTuning]

Excellent! Very glad we could help. Have fun at the track and Stay Tuned!

[@evergreenpsyche]

I learned a lot from this, thank you! Like BlueWffl I am also wondering about DOT 5.1 usage but it sounds like DOT 4 is pretty adequate as long as you pick the right brand.

[@FlatironsTuning]

Thanks for your question. From what I can recall, DOT 5.1 is compatible with DOT 3 and DOT 4. The main difference is that the DOT 5.1 has a higher boiling point than the minimum required for DOT 3 and DOT 4. But that being said, the fluids here are well beyond the minimum spec of the DOT 5.1, so these DOT 4 fluids would be your best option for your car most likely. DOT 5.1 may have some other specs that don't fall within the DOT 3 and DOT 4 requirements as well. The safest bet is to stay with DOT 4. I hope that helps, thanks for watching and Stay Tuned!

[@Stolo17]

Great video, thanks!

[@FlatironsTuning]

Thanks for watching and glad that the video helped. Stay Tuned!

[@raulmunoz4023]

👀👀👀WARNING and MISTAKE - DOT-4 is NOT SILICONE-BASE. ONLY DOT5 IS SILICONE BASE - BIG MISTAKE in the video DOT3/DOT4/DOT5.1 ARE COMPATIBLE

[@bradleycole2655]

Lifesaver

[@BajaWRX]

Thanks for all the info you guys provide, been really helpful while currently rebuilding a WRX 2.0 engine. You guys bring up a lot of interesting topics that make me go back and double check my build process and change some things just for the engine health and reliability. I'm not on social media anymore to ask you this question that I haven't found an answer to but it's this, What is the difference between the Walboro 255 and the 255 High pressure variant and under which situations would you run one or the other?

[@FlatironsTuning]

That is an interesting question. I'm not sure what the exact difference is. If we can find out anything useful, we'll let you know! I'll just mention that the standard GSS342 Walbro has been well proven, and would be a solid choice. Thanks for watching and Stay Tuned!

[@nrgzrbny]

Something they didn't touch on for street cars , ~2012+ ABS systems typically now require a low viscosity formulation (DOT 4LV / DOT 4 Class 6)

[@balazsszirmai8906]

Hi, What would be the best fluid for a daily use 400 HP 2019 Golf R (DOT4)? Possible tracking in summer. But in the 70% of the cases I am normally driving that lovely machine. Thanks in advance!

[@jeffcandobackflips]

When switching dot 3 to dot 4 in the brake system, would you bleed the clutch also so that the clutch will recieve the dot 4 and not introduce old dot 3 into the system?

[@sootherelax2802]

You know I’m really impressed with Amsoil brake fluid. The dot 3 and 4

[@FlatironsTuning]

Very glad to hear it. Thanks for watching and Stay Tuned!

[@Wolfpack310]

I use mannol dot 4 Its colorless like water and works nice in my car

[@PITBOY911]

Does anyone have experience with VP Racing 622 brake fluid?

[@bbehzadi413]

I’ve heard good things about Castrol Srf racing fluid wonder what you’re thoughts on it are for an aggressive street/auto cross car?

[@FlatironsTuning]

Thanks for your question. Castrol SRF is good fluid, but it is really, really expensive. It was designed for very high performance motorcycles, so the cost for them isn't so bad, but it makes switching to that fluid in a car pretty expensive. It has a dry boiling point of 325 C, which is right in line with the Ferodo Super Fluid and Motul RBF 660. But the big difference is the wet boiling point. Castrol SRF has a wet boiling point of 275 C which is fairly close to its dry boiling point, and that is much, much higher than those other fluids. So the Castrol SRF will need to be bled less often. If you have a car that sits for longer stretches of time, and you don't want to have to bleed the fluid before you take it out. The SRF may be a good option. But if don't mind bleeding the brakes every so often, the other DOT 4 fluids may be a good fit for you. Hope that helps and Stay Tuned!

[@alexudolkin2146]

Great topic! Is it true the fluid becomes compromised by air/humidity exposure if you don’t end up using the whole bottle of brake fluid? Surprised the oem Subaru fluid didn’t make it into this comparison. Thanks!

[@FlatironsTuning]

Thanks for your question. Yes, brake fluid will pull moisture from the atmosphere as we discuss in the video. So you are correct, if you have an open bottle that has sat on the shelf for more than a month or so, it will start to have a lower boiling point, etc. Since the Subaru brake fluid is only DOT 3, all of the options discussed here will have a higher capacity. Thanks for watching and Stay Tuned!

[@anotherstar8125]

is the rbf600 safe to use on the street?... im looking to upgrade to Stoptech Stainless Steel Brake Lines, DBA T3 4000 Series Slotted Brake Rotors, and G-LOC GS-1. what brake fluid do you recommend for a daily driven car that gets in about 2 spirited mountain drives per week?

[@FlatironsTuning]

Thanks for your question. Yes, you can absolutely run that fluid year round. I'd recommend bleeding your brakes each year just to make sure that the fluid stays fresh. Hope that helps and thanks for watching. Stay Tuned!

[@anotherstar8125]

@@FlatironsTuning Thanks for such a quick response! Your content is awesome!

[@buggzo]

What do you recommend for a fast doordashing delivery car that is slamming on the brakes every few blocks for 12 hours a day?

[@FlatironsTuning]

Thanks for watching and thanks for the question. You would be fine with the Motul RBF600. It has plenty of capacity for the street. Hope that helps and Stay Tuned!

[@davidoneill9442]

I dont much about brake fluid but I know im going to change my cars from DOT 3 to DOT 4. 2 Months ago after heavy braking on a downhill switchback road . i had catastrophic brake failure in my rear (Drum Brakes) wheel drive Toyota Fortuner 3.0L. I was told this is common in Fortuner , Hilux and Innova The garage said the back brake pads were broken. I stopped the car by crashing head on into concrete safety barrier over a drain pushing the engine back 20 inches, either that or the cliff. The car was a total wreck, My new Fortuner has 4 Disc Brakes

[@FlatironsTuning]

Brake failures are never fun, and very sorry that you went through that. Keeping your brakes in good condition, and using good fluid are great ways to keep the chance of that happening again to a minimum. Thanks for watching and Stay Tuned!

[@rajZ772]

which break fluid is suitable for Toyota Etios GD Diesel?

[@zd141]

genuine

[@mdev8846]

In my opinion, Endless RBF 660 is the best brake fluid.

[@FlatironsTuning]

Thanks for the comment. Stay Tuned!

[@RobHTech]

Ya but when you flush the system to replace the fluid, I presume that you need to also drain the caliper itself too.

[@FlatironsTuning]

Thanks for your question. The brake system and clutch system are separate. So the brake bleeding system should be no different. Thanks for watching and Stay Tuned!

[@lilbreezi1243]

What would be the best for a daily that I drive pretty hard in the canyons once a week?

[@FlatironsTuning]

Thanks for watching and thanks for the question. For that, Motul RBF600 would be a solid option. Stay Tuned!

[@FlatironsTuning]

Thanks for watching and thanks for the question. For that application, Motul RBF600 would be perfect. Hope that helps and Stay Tuned!

[@TeamSimpsonRacing]

Is the 660 the best for racing or is there an even better option?

[@FlatironsTuning]

Thanks for your question. From our experience, the Ferodo Super Racing or Motul RBF660 are both very good. Just make sure that the rest of your braking system can tolerate the higher temps that those fluids will create in your calipers, etc. Hope that helps and Stay Tuned!

[@PotholesInMyLawn]

I would hate to see his boiling point if you take his red stapler !

[@LoneWolf91]

This is such a great comment! 😂😂

[@Hawkfeet]

Is lucas dot 4 good for a camry And does synthetic mean that it lasts longer or what?

[@FlatironsTuning]

For a Camry, OE fluid should be fine. But you could go up to a DOT 4 if you like. Generally the DOT3 fluid will last a bit longer than the DOT 4. Thanks for watching and Stay Tuned!

[@Hawkfeet]

@@FlatironsTuning but why it last longer?

[@FlatironsTuning]

@@Hawkfeet Because it will not absorb moisture from the atmosphere as quickly.

[@Hawkfeet]

@@FlatironsTuning performance wise Is there a difference or just a higher boiling point

[@edbo10]

@@Hawkfeet dot 4 will boil at a higher point than dot 3, at the expense of absorbing moisture quicker from the ambient air than dot 3

[@bluewffl8472]

What about motul DOT 5.1? Bought some, haven't flushed it yet...02 wrx here with 06 calipers in front and factory sliders in rear. Opinion? I drive it hard on the street/light autocross atm...

[@aersoul]

5.1 does not so well in street car applications for the reason of ABS. It is very prone to aerating so if you were to get into an ABS event the fluid could very likely aerate due to the valves cycling and your pedal would get long or might not be there at all the next application. DOT 5.1 really only belongs on racecars that get their brake fluid maintained regularly due to how much moisture Dot 5.1 pulls from the atmosphere. Would not recommend on a street driven car even if you track/autocross it. Dot 4 is your safest bet.

[@FlatironsTuning]

Thanks for your question. From what I can recall, DOT 5.1 is compatible with DOT 3 and DOT 4. The main difference is that the DOT 5.1 has a higher boiling point than the minimum required for DOT 3 and DOT 4. But that being said, the fluids here are well beyond the minimum spec of the DOT 5.1, so these DOT 4 fluids would be your best option for your car most likely. DOT 5.1 may have some other specs that don't fall within the DOT 3 and DOT 4 requirements as well. The safest bet is to stay with DOT 4. I hope that helps, thanks for watching and Stay Tuned!

[@FlatironsTuning]

@@aersoul I hadn't heard that issue with the DOT 5.1. Thanks for posting, and Stay Tuned!

[@evergreenpsyche]

@@FlatironsTuning @Javier Rios That's interesting because I had someone tell me that DOT 5.1 is actually engineered to not absorb any moisture at all. Hmmm....time to do some research!

[@evergreenpsyche]

​@@aersoul Was intrigued by your comment and did some further research -- I think your facts may be a little mixed up (no offense)....it is DOT 5, the silicone based fluid, which aerates easily and doesn't work with ABS. However, it does not absorb any water, nor does it disperse it, so it does have some issues with causing corrosion over extended periods and needs more frequent service intervals. It's also more compressible than glycol based fluids so not ideal overall DOT 5.1 is glycol based and has very similar properties to DOT4. It's just hella more expensive, and in reality it has similar temperature ratings to some of the premium DOT 4 brands (which have far exceeded the minimum DOT4 ratings). Edit: Originally I said DOT5.1 can't compete on price, but looking at Motul 5.1 vs RBF600 (the "street" fluid), the 5.1 definitely has better performance and similar pricing so I'm not so sure. 5.1 might be the way for street use.

[@florenbaron7111]

Cam you mix DOT 3 and 4?

[@FlatironsTuning]

Thanks for your question. Yes, you can mix them, but the DOT 3 negates the DOT 4. If you need the higher boiling point, you will want to flush out all of the DOT 3. Hope that helps and Stay Tuned!

[@kykypenn]

What’s the best brand for the dot 3

[@FlatironsTuning]

For dot 3, it doesn't make much difference. I'd recommend Subaru OEM. Thanks for watching and Stay Tuned!

[@kykypenn]

@@FlatironsTuning isnt the boiling points and stuff different for each dot 3

[@FlatironsTuning]

@@kykypenn They would all be lower than DOT 4. If you want a higher boiling point, then you would want the DOT 4 fluid. If you don't need the higher boiling point, then your best bet is to stay with the OEM fluid that is designed to work with the car because that would have a sufficiently high boiling point.

[@kykypenn]

@@FlatironsTuning I don’t have a racing car I have a sxt challenger though. so I don’t think the boiling point would need to be high but would the wet boiling point need to be high?

[@mdev8846]

AP RACING R1 is the best DOT 3. A lot of Japanese cars have the same DOT 3 for brake fluid and cluth fluid.

[@nexushexus4365]

ATE brake fluid makes the brake pedal squeaky.

[@user-vc9ig3pf5y]

I have tried dot 4 big mistake. For Mr and Mrs average just use dot 3 to be successful need to replace bra!E parts