brake fluid recommendations

[frootloops]

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?

[shnazzle]

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

[frootloops]

Okay, thanks for the reply. I'll look up ate 200

[dan944]

Motul rbf660. It's the dogs danglers as far as brake fluid goes

[shnazzle]

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

[1979scotte]

From what i have been told  ATE 200 is a good compromise between price and performance.

[shnazzle]

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.

[frootloops]

Cheers guys, appreciate the advice. For reference its for fast road use and will be used with standard discs, braided lines and greenstuff pads.

[shnazzle]

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.

[trickyD]

I had good results (Lack of brake peddle compressibility) from AP Racing 5.1
Never faded but I never tracked it.

[Topdownman]

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?

[james_ly]

I've used Pagid 5.1 for years. Change once a year on track cars, always had the pads fade before the fluid.

[Kaveney]

At the price this is very good and the one i use .

Motul rbf660. It's the dogs danglers as far as brake fluid goes

[Topdownman]

Its the quantity that I would need that is my main question.

[thetyrant]

1 litre will be enough to change it, if you plan on flushing a lot through get an extra 500ml just in case

[Topdownman]

Great, thanks!

[Dev]

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.

[thetyrant]

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.


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

[Dev]

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.

[mrzwei]

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.

[Dev]

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.

[shnazzle]

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

[Dev]

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.

[Call the midlife!]

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]


Sent from my iPhone using Tapatalk

[shnazzle]

Indeed. I got two bottles of rb600 for 10 quid so they're going in next time wwhy not eh.