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We answer some of the most frequently asked questions from the world of performance braking


You probably don’t need us to tell you that there are often a large number of myths and debates revolving around the world of vehicle braking. In this article, we aim to answer some of these queries once and for all…
Photo: EBC Brake Fluid
Q) How often should brake fluid be changed?

A) Every two years for normal road use, or every 2-3 visits to the race track for a vehicle used frequently on the circuit.

Q) How do I choose the right type of brake fluid?
A) Most vehicles use Glycol DOT 3 or DOT 4 fluid – see the top of your master cylinder or owner’s manual for more info.

Q) What’s the difference between DOT 3/4/5 brake fluids?
A) DOT 3 and 4 are effectively the same, with DOT 4 being purer. DOT 5 can be silicone or glycol variants and cannot be interchanged with DOT 3/4.

Q) What type of brake fluid is used for racing?
A) A DOT 4 high-temperature version is best, such as EBC’s BF 307 fluid.

Q) What is ‘dry boiling point’ and ‘wet boiling point’?
A) The dry boiling point refers to when fluid is new from an unopened bottle. The wet boiling point is when the fluid is used and needs changing (where the water content is past 3%).

Q) Why is dry boiling point higher than wet boiling point?
A) This is because the moisture content of a brake fluid boils at a lower temperature, therefore the wet boiling point will be lower.
Blue Apollo Caliper
Q) What are brake caliper seals made of?

A) Most vehicles use EPDM rubber, while a few use Nitrile rubber. A third, rarer version is Viton.

Q) How often should brake caliper seals be changed?
A) Every 2-3 years in road use, or every few races on the track, or if the caliper body reaches temperatures over 250°C.

Q) What is the maximum safe temperature for caliper seals to be exposed to?
A) EPDM seals (the most popular type) are not designed for use above 140-150°C, which corresponds to a caliper body temperature of about 250°C.


Q) How hot do my discs/rotors get and what does this mean for my pad compound selection?
A) Heat paints are a handy tool in telling you exactly what products you should be using.
EBC Brakes offers three heat paints which can be brushed onto the outer edge of the rotor before racing, to detect temperatures. The EBC Brakes rotor paint kit also includes 10 caliper heat strips.
The rotor paints supplied are:
#1 – 800°F/430°C
#2 – 1000°F/540°C
#3 – 1200°F/650°C

Paint all three separately in lines on your disc/rotor edge.
The temperature at the centre of the brake pad will always be on average 100°C/200°F more than the outer edge of the rotor in race use. If your rotor edge is not setting off the 430°C paint line, all EBC compounds will be fine.
If the 430°C paint line activates (530°C at the centre of the pad), you’re at the limits of EBC’s Bluestuff pad.
If the disc/rotor outer edge temperatures exceed 540°C (640°C approx. at the pad centre), you are past the limits of EBC’s Bluestuff and need to switch to EBC Brakes Racing’s RP pad range.
If the 650°C paint line goes off (750°C at the pad centre), you’re definitely in need of either the RP range or SR series of pads.
Here is a guide on EBC Brakes compounds and their temperature ranges:
The curves below show that on average in race use, the pad temperature runs at approx. 100°C above the disc/rotor outer edge:
 

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2018 Giulia Ti Sport Q4
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SO that's why my yellowstuffs got cooked at Road America and then felt like bars of soap on the road afterwards. LOL I thought they were a bit higher temp.
 

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2018 Vulcano Black Giulia Quadrifoglio
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This may be a silly question, but if blue stuff scored better in every category than yellow stuff, why would that not be a better compound of choice for the street?
I thought that street compounds are good for warming up faster for street use, vs track pads that bite harder but take longer to get there at first. But this chart shows yellow stuff as having the lowest bite from cold
 

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Sadly EBC doesn't make blue stuff for a Giulia TI Sport Q4. Some of us will destroy a set of yellows even with the normal model. Its sad they only seem to really focus the better stuff on the Quadrifoglio when the majority of cars sold are base or TI models. Because of this I will not be using them.
 

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2019 Giulia Ti Q2, Performance Pack
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Can you all speak to the differences between your rotor metallurgy vs cheaper or less advanced ones?
 

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Discussion Starter · #6 ·
SO that's why my yellowstuffs got cooked at Road America and then felt like bars of soap on the road afterwards. LOL I thought they were a bit higher temp.
Did you have yellow front and rear critical for proper performance particularly on track?

Any track use will affect the surface of the pads and may take a hundred miles or so to recover.
 

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Not a brake expert, but lots of experience with OEM, aftermarket, and custom molded track pads on various cars. What I used to often do was to put a "glazed" pad on my belt sander for a few seconds, and remove the shiny surface,. There is a concept called "adversion", I think it is called, where the interface between pad and rotor are is a complex interaction, a lot more complex than just "friction." Pedal shudder when slowing can happen when this layer of pad deposition is uneven on a rotor. In times past, I sometimes cleaned all pad residue off of my rotors, and then re-applied an even layer with a bedding procedure. There is also something that may happen, when a rotor has uneven heating, changing the structure of the iron, or something like that.

All I know is that pad science is a "black art" and is far too complex for me to understand.

Then there is caliper design. One of my friends recently retired from an engineering career at a major brake pad manufacture. He describes things to me I just can't understand.

NV
 

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2018 Giulia Ti Sport Q4
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Did you have yellow front and rear critical for proper performance particularly on track?

Any track use will affect the surface of the pads and may take a hundred miles or so to recover.
Yellows front and rear. After my first session, you could really smell them. The worked OK for the remainder of the two day event, but then afterwards on the road they were not the same. I had many thousands of miles after the event, and didn't notice much change. Blues or RPn would have been better.

BUT!!! Prior to the track event, I really liked the feel of the yellows on the street. They are also nice and quiet.
 
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