I'm going to change the brake fluid to dot 5.1 while fitting braided lines and wondered if anybody had any recommendations on which brand to go for?
I used ATE type 200. Very pleased so far. I bled it a bit after a big run with lots of braking and no air came out.
It's DOT4 though. Don't stare blindly at 5.1. A good 4 can be better and have higher boiling point than a 5.1
Okay, thanks for the reply. I'll look up ate 200
Motul rbf660. It's the dogs danglers as far as brake fluid goes
It is indeed but it's expensive and not recommended for road use. Although I know plenty do run it on the road. Especially the 660, it's really intended for track use
From what i have been told ATE 200 is a good compromise between price and performance.
Castrol SRF is what you want if you're just after dog's reproductive glands. Never tried it but when I did a search a whole ago, this was what the big boys want.
Cheers guys, appreciate the advice. For reference its for fast road use and will be used with standard discs, braided lines and greenstuff pads.
ATE is your choice then if you ask me. No use wasting cash on rbf600 or 660
Actually... Any old 5.1 will do haha. You're unlikely to get to boiling point on fast road. If so, very rarely.
The braided lines are going to give you the brake response, as are the pads. Invest in that.
I had good results (Lack of brake peddle compressibility) from AP Racing 5.1
Never faded but I never tracked it.
No point starting a new thread!
The ATE type 200 seems to be the fluid for me , my question is how many litres will I need?
I've used Pagid 5.1 for years. Change once a year on track cars, always had the pads fade before the fluid.
At the price this is very good and the one i use .
Quote from: dan944 on April 20, 2015, 06:07
Motul rbf660. It's the dogs danglers as far as brake fluid goes
Its the quantity that I would need that is my main question.
1 litre will be enough to change it, if you plan on flushing a lot through get an extra 500ml just in case :)
Great, thanks!
Im probably going to go against the grain here about brake fluid.
I have used DOT4 and DOT5.1 brake fluid and it was a complete waste of money for the following reasons.
I never experienced fade with factory DOT3 fluid even though I only drive on the street.
I have never heard of anyone boiling their fluid who raced using DOT3 for our cars. The fade is usually from the pads and after a pad change they had no issues.
When using DOT 5.1 and DOT 4 for an extended time of over one year I was having a wooden pedal in the cold because both are more viscus. My pedal travel was restricted and I lost modulation. In the summer I started seeing brake fade which made me change the fluid.
What I found out was DOT 4 and its variants like DOT 5.1 are more viscus. If they take in a little moisture they will drop off performance quickly and can cause fade so they have to be changed frequently. DOT 3 on the other hand can hold more water and the braking performance will not be as effected.
This is not to say DOT 4 is bad in all applications and some cars call for DOT 4 fluid and are engineered with the master cylinder and seals to handle the higher viscosity. Our cars specify DOT 3 and I found that it works better from a practical perspective.
What suggest is to use DOT 3 especially in a street application. If its for a race application I would use fresh DOT 3 and only when you are actually experiencing fade due to boiling the fluid then I would upgrade to the DOT 5.1 and change it out frequently. I found the Toyota DOT 3 red bottle brake fluid to be the best and thats all I use now.
I should hope you havent boiled the fluid with road use as temperature are much lower than track generally, pretty much any fluid in decent health (moisture content) will handle road use with even spirited driving on these cars due to light weight and decent sized brakes etc, however take it on track with a high temperature track pad and its a whole different ball game of course and you then need a high temperature fluid to keep pedal hard :)
Most track capable fluids are Dot4 as its much more developed than Dot5.1, which while in basic spec has higher point than a basic spec dot4 its a good distance behind a race spec dot4 like Motul RBF600 or the daddy which is Castrol SRF due to its amazing wet boiling point, dot5.1 is a very thin fluid primarily designed for the intricate workings of ABS systems and many wrongly think because of the higher number it has a higher boiling point, which as above is not the case when comparing to race spec dot4 fluid like the RBF and SRF dot4's i mentioned.
I work in the high performance brake pad industry and brake fluid is the probably the most neglected thing i come across, the amount of customer who buy and fit expensive.high performance track pads from me but ignore the fluid is crazy, then complain when pedal goes mushy out on track.
I recommend a bleed of calipers between every couple of track outings with full fluids change every 6-12months depending on the car, road only car every 2 years which maybe a bit over the top but having had a car that was very hard on fluid due to big power increase and tiny brakes ive always kept well on top of fluid,nothing worse than soft pedal spoiling your trackday and trying to bleed hot brakes in the paddock!
Edit to add some data, first is a generic brake fluid spec taken from wiki site (https://en.wikipedia.org/wiki/Brake_fluid) and typical for a base spec fluids.
(http://carbotech-europe.com/brakefluid1.jpg)
Next some what i would call track spec Dot4 fluids, just look at that SRF wet boiling point compared to RBF which in itself is a very good fluid and what i generally use and just keep it fresh.
MOTUL RBF600
Viscosity at -40°C 1750 mm2/s
Viscosity at 100°C 2.5 mm2/s
Wet boiling point 205°C
Dry boiling point 312°C
Castrol React SRF Racing
Viscosity at -40°C 1300 mm2/s
Viscosity at 100°C 3.5 mm2/s
Density at 20°C, relative 1.066 g/ml
Wet boiling point 270°C min
Dry boiling point 320°C min
Im not doubting the advise at all however I think its best to graduate to better brake fluid and pads once you experience fade.
I think everyone should experience what fade is like just for the experience. Most that drive this car in particular will probably never experience fade with DOT 3 especially if they are new to the track and are primarily street drivers. The problem often is people buy the better bake fluid which is not needed especially for a street application. There are downsides as I mentioned with the high-performance brake fluid as well as pads for long term use in a street application as the braking performance can have a rapid drop-off once its moisture contaminated.
I experienced brake fade on the A2 Autobahn when braking from about 130K behind a stau (jam). At first the brakes gripped but then the harder I pressed just went dead. Really scary, how I stopped without rear ending I'll never know. That was in a company Opel combi, so it's not just about track use.
Quote from: mrzwei on March 23, 2019, 00:27
I experienced brake fade on the A2 Autobahn when braking from about 130K behind a stau (jam). At first the brakes gripped but then the harder I pressed just went dead. Really scary, how I stopped without rear ending I'll never know. That was in a company Opel combi, so it's not just about track use.
Of course, it's not just about track use. I have experienced brake fade on the street, it can happen when a car is not properly maintained. It can also happpen with high performance bake fluid that is not changed out early.
It also depends on the kind of car and the braking system including the ventilation.
With normal brake fluid changes for most cars you should not experience fade on the road in most situations. Possibly mountain passes and towing but it is rare.
I think you nailed it Dev in that it's about maintenance.
It's the same with engine oil and spark plugs.
I have experienced brake fade on the long downhill section of the Hartside Pass, but the fluid had never been replaced. It was quite bad and I'm obviously boiled the crap out of it as the brakes were never the same after that until I flushed the fluid with ATE200 and put on some braided lines.
The ATE200 (Dot4) was great, until it wasn't.
It's track fluid that's meant to be changed after each track day. High boiling point but more hygroscopic. So, within a few months of spirited driving and sitting outside, the brakes were spongy again.
I replaced it with 5.1 because the car sits outside in hot/cold and I wanted it to last. Haven't had issues since but almost 2 years on, it's starting to feel like it needs replacing again.
It's maintenance... You can buy fancy Iridium spark plugs, or you can buy cheap coppers and change every 6 months. You can buy 50 quid Fuchs oil (as I did do religiously), or buy 30 quid oil and replace 2x a year. Etc etc
Quote from: shnazzle on March 23, 2019, 07:21
I think you nailed it Dev in that it's about maintenance.
It's the same with engine oil and spark plugs.
I have experienced brake fade on the long downhill section of the Hartside Pass, but the fluid had never been replaced. It was quite bad and I'm obviously boiled the crap out of it as the brakes were never the same after that until I flushed the fluid with ATE200 and put on some braided lines.
The ATE200 (Dot4) was great, until it wasn't.
It's track fluid that's meant to be changed after each track day. High boiling point but more hygroscopic. So, within a few months of spirited driving and sitting outside, the brakes were spongy again.
I replaced it with 5.1 because the car sits outside in hot/cold and I wanted it to last. Haven't had issues since but almost 2 years on, it's starting to feel like it needs replacing again.
It's maintenance... You can buy fancy Iridium spark plugs, or you can buy cheap coppers and change every 6 months. You can buy 50 quid Fuchs oil (as I did do religiously), or buy 30 quid oil and replace 2x a year. Etc etc
Give me a day and I will show you with sources the big myth surrounding DOT 4 and DOT 3 brake fluid compatibility and how it actually works in the real world. This is what most do not discuss because the information is hidden.
Well I'm sticking Dot 4 in mine, mainly because I've got 2 litres of expensive stuff I ordered in the certainty that it's what I needed [emoji23]
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Indeed. I got two bottles of rb600 for 10 quid so they're going in next time :) wwhy not eh.
Used to put SRF in my fun road car (over 700bhp/ton and weighs 1750kg) but needed changing once a year and have used Motul RBF660 for the past couple of years. Absolutely no issues with repeated stops from over 200mph on runway days.
SRF also eats seals but for track use it is the ultimate.
Not all brake fluids are alike even in their respective DOT ratings as there is so much variation. It is a common myth that you can always substitute one for the other except in the case of DOT 5 but not always. There is also more to brake fluid in regards to its viscosity, seal and corrosion protection.
Here is the white paper that is published from Centric Parts that I will be quoting from.
https://www.apcautotech.com/getmedia/026dfcc4-906a-4f74-961d-4df6123cdca8/brake-fluid.pdf
I will also be quoiting from this article.
https://www.aa1car.com/library/bfluid.htm
There are many cars where DOT 4 fluids are not compatible because the viscosity is just too thick for cold weather performance especially in applications where they use ABS and traction control mechanisms in colder climates. In cases like this they use low viscosity DOT 4 and other variants that were made to address this issue, they cannot use regular DOT 4 fluid.
DOT 4 fluid that is used in a car that was designed for DOT 3 can have other damaging effects that might not be apparent immediately due to its chemistry and viscosity.
QuoteAs a trailing note on the DOT ratings, if your car was designed for a particular type of fluid (especially prior to the development of DOT 4 fluids), you should make every attempt to stick with that fluid! For example, if your car was delivered with DOT 3 fluid, the internal components of the system (seals, brake hoses, and fittings for example) were specifically designed and tested for compatibility with DOT 3. Because DOT 4 fluids contain a different chemical composition, the system may not necessarily react in a positive fashion to the borate esters floating around in the mix.
In other cases, just the difference in viscosity of the two different fluids may cause the seals to wear at different rates. What starts as an annoying squeak might eventually become a torn seal or worse. The examples could go on and on, but the message here is this: it's fine to upgrade from DOT 3 fluid A to DOT 3 fluid B, but you should think twice (maybe even three times) before switching from DOT 3 fluid A to DOT 4 fluid of any sort.
As far as DOT 4 being changed out early because its more hygroscopic than DOT 3 is a widely circulated myth. Actually it is the other way around.
QuoteA seldom talked about characteristic though is that because of this chemistry, the DOT 4 fluid will have a more stable and higher boiling point during the early portion of its life, but ironically once the fluid does actually begin to absorb water its boiling point will typically fall off more rapidly than a typical DOT 3. By FMVSS116 standards, DOT 4 fluids must have a minimum dry boiling point of 446F and a minimum wet boiling point of 311F.
Does this make DOT 4 fluids better than DOT 3 fluids? Not always. Remember, the boiling points listed are minimums and there are DOT 3 fluids out there with higher boiling points than some DOT 4 fluids. The real differentiating factor should be that if you run a DOT 4 fluid you really should change the fluid more often than if you use a DOT 3, if for no other reason than the rapid fall off in boiling point with time.
QuoteDOT 4 fluid, which has a higher minimum boiling temperature requirement (446 degrees F dry and 311 degrees wet) soaks up moisture at a slower rate but suffers an even sharper drop in boiling temperature as moisture accumulates. Three percent water will lower the boiling point as much as 50%!
From my own personal experience I was using DOT 4 and DOT 5.1 at some point in time. I actually bought a case of DOT 5.1. I used it like regular DOT 3 as a daily commuter and about a year later when temps dropped I noticed that the pedal became wooden. I lost modulation and didn't know why. When spring came I went for a spirited drive and experienced brake fade in a bad way. I also used the stuff for my clutch and I started having shifting problem from poor disengagement. Once I flushed the fluid I was fine for a time but the grinding returned.
After going back to Toyota DOT 3 fluid the pedal was much better and I never experienced a problem like this ever again. I believe the Toyota fluid offers the correct viscosity and corrosion inhibiters to keep the brakes in perfect order. Also I can go over 2 years with the fluid and never experience a lick of fade.
There is a good reason why DOT 3 fluid is used in most passenger vehicles simply because it's forgiving in real world conditions. If you use DOT 4 fluid be sure to change it out early because the braking system is not perfectly sealed for DOT 4 and moisture enters into the breather and the seals of the pistons. Its further contaminated when you drive in rainy conditions which can easily drop the boiling point drastically for DOT4 fluid and give you a nice surprise when you need the brakes the most.
In regards to racing I would just use fresh Toyota DOT 3 fluid until you notice brake fade, at that point in time you will know that going to DOT 4 was a necessary upgrade and a milestone.
One more link in regards to boiling capacity.
https://cartreatments.com/dot-3-vs-dot-4-brake-fluid/
I guess my experience marries up to that with the DOT4. I guess it wasn't that it was more hygroscopic, but the heightened effect on the boiling point. In any case brakes felt sh1t. Flushed it with 5.1 and problem went away. That was over a year ago now and it still brakes absolutely fine, but there's nothing like the feel of a crisp, freshly bled brake system, so I'm flushing it soon and I got a good deal on the RBF so it's going in :)
Interesting read though. Next batch will be DOT3 I guess. Saves money too
Quote from: shnazzle on March 24, 2019, 07:19
I guess my experience marries up to that with the DOT4. I guess it wasn't that it was more hygroscopic, but the heightened effect on the boiling point. In any case brakes felt sh1t. Flushed it with 5.1 and problem went away. That was over a year ago now and it still brakes absolutely fine, but there's nothing like the feel of a crisp, freshly bled brake system, so I'm flushing it soon and I got a good deal on the RBF so it's going in :)
Interesting read though. Next batch will be DOT3 I guess. Saves money too
There is another good reason to use only Toyota brake fluid. The formulation is specific for the seals and metals of the car.
Although this does not effect our cars it has caused trouble when other Toyota cars and trucks used different brake fluid.
http://media.fixed-ops.com/Toy_Campaigns/a0m.pdf
QuoteDuring vehicle assembly, Toyota uses brake fluids containing polymers that act as lubricants for certain brake system components. If replacement brake fluid is used that does not contain such polymers, or contain only small amounts, a part of the rubber seal (Brake Master Cylinder Cup) located at the rear of the brake master cylinder may become dry, and the rubber seal may curl during movement of the piston. If this occurs, a small amount of the brake fluid could slowly leak from the seal into the brake booster, resulting in illumination of the brake warning lamp.
• If the vehicle continues to be operated in this condition, the brake pedal feel could change, and braking performance could eventually begin to gradually degrade. If the warnings provided by the lamp illumination and the change in pedal feel are not heeded, a vehicle crash could occur.
• Toyota original brake fluid which is applied at the manufacturing plant contains polymers and does not cause this phenomenon
Honda had a similar issue with corrosion using non Honda brake fluid.
One of the most basic indicators that you shouldn't use DOT 4 fluid is on the reservoir cap which states use DOT 3 fluid only. On some other Toyota cars they will state DOT 3 and DOT 4 compatibility.
It is believed that although Toyota fluid claims meeting DOT 3 specifications it might actually exceed it and will be much higher.
There are a lot of hidden truths to fluids of all types.
Quote from: Dev on March 24, 2019, 07:36
There is another good reason to use only Toyota brake fluid. The formulation is specific for the seals and metals of the car.
Although this does not effect our cars it has caused trouble when other Toyota cars and trucks used different brake fluid.
So any normal fluid works? Phew!
Quote from: james_ly on March 25, 2019, 10:38
Quote from: Dev on March 24, 2019, 07:36
There is another good reason to use only Toyota brake fluid. The formulation is specific for the seals and metals of the car.
Although this does not effect our cars it has caused trouble when other Toyota cars and trucks used different brake fluid.
So any normal fluid works? Phew!
I don't think anyone knows however the formulation of the Toyota brake fluid was optimized for the car. There is a good chance that the seals and metals will last longer. Honda makes it clear for their car that you should only use their brake fluid otherwise you risk corrosion.
Also there is a very good chance that Toyota bake fluid has a much higher dry and wet boiling point as it is advertised to be heavy duty and high temp.
It is also the factory fill and specified in the manual for the Lexus ISF, LFA super car and heavy duty trucks and SUVs. If this fluid can handle those applications it should be more than sufficient for ours.