10k words about brakes! everything you need to know about every part of your brake system.

10k words about brakes! everything you need to know about every part of your brake system.

I wanted to dive into the world of brakes, and share some of the experiences I’ve encountered over the years. As many of you know the internet can be a very helpful place, but it can also be full of misinformation, subjective opinions, and flat-out incorrect answer’s. With this blog post I want to try to help clarify any misinformation and just help you understand how every aspect of you braking system plays a key role in how the whole system works. No crazy long back story here, let’s just dive right in. If you follow me on Instagram you will know that my proportioning valve was leaking on my EG, which lead me to want to make this post to help guide you through the confusing world of brake upgrades. Functiontheory is heavily influenced with Honda related content, this is mainly because currently I have two civic’s, and I’m very experienced in Honda’s, so it comes natural for me to only be doing Honda content. However Functiontheory is NOT a Honda only blog, it’s a blog for functional cars by functional cars, to help aid in the building of cars that actually get driven and used for what they were built for, and not just “the gram.” The below article will go into detail about every part of your braking system. I throw in me working on my EG and reference typical Honda brake setups because that’s why most of you are here… to learn how to improve your Honda’s braking system. But the knowledge is transferable to any make or model, and I’m confident that if you read the whole thing you will learn a tremendous amount, which you can then use to improve your cars brakes, and share with the world to help dispel all the wrong information out there.

BRAKE FLUID:

Brake fluid is one of the most overlooked or neglected fluids in your car. Some people will go the whole life of their car never changing it. To truly understand why brake fluid is important we must start with some key things about brake fluid. Brake fluid is a Hygroscopic fluid, which means that brake fluid will actually attract and absorb moisture from the air. That’s right! no matter how tight you have the cap on your brake fluid reservoir, moisture is going to get in there. Now for a brake system to be considered “saturated” with water we are only talking 3.7% by volume. Just plain old DOT 3 fluid can absorb water at a rate of 1-2% per year, so even the most under estimated number can put you at just about 4 years before you whole system is considered “saturated.” Why  is having water/moisture in your brake fluid a bad thing? Well… brakes work through kinetic friction which a byproduct of this is heat. The heat can easily reach 300-500 degrees Fahrenheit under normal street driving and almost 1000 degrees Fahrenheit under extreme track conditions. Water boils at 212 degrees Fahrenheit, and with just average daily driving temps for brakes well above that, the water in the brake fluid will boil and become steam. Steam is a gas and is much more easily compressible than the fluid is, as a result your pedal will become spongy. This will directly affect your braking system, and could even cause your brakes to not slow you down as quickly in an emergency situation due to lack of pressure being applied to the calipers/drums. The amount of PSI for a normal operating brake system should be between 800-1200 PSI (now obviously this depends on what your application is, and how old or new your car is.) I’m only saying those numbers so you get just a rough idea of how much PSI is in your brake system. Also moisture in the brake system can cause ABS/traction control systems to not function properly, and can cause internals of the brake system to rust or deteriorate. Now don’t think because your car isn’t driven that often you won’t have to worry about this. Unlike most things on a car the amount of mileage you put on the car doesn’t directly affect the fluids life. (well yes it does to a certain extent if you are driving under harsh conditions) but you could put 20,000 miles on your car in one year, or zero miles on your car and theoretically you brake fluid will still be absorbing water. Now of course this greatly differs based on the climate of where you live (relative humidity levels of your geographic location) But again I’m only telling you all this to just educated you on the importance of brake fluid change intervals. There are ways to test your brake fluid to see if it’s bad or not, you can just go to a local auto parts store and get some test strips, or buy special tools that electronically test the fluid (which is more accurate) but not always necessary. Most auto repair shops have those tools and can test it for you for a few bucks or even free, because it’s a great way for them to talk you into getting your brakes serviced with them.

Now let’s talk about the different “grades” of brake fluid, and which is best for you.  The U.S. Department of Transportation classifies brake fluid into four main categories of brake fluid, DOT 3, DOT 4, DOT 5, and DOT 5.1. The main difference between the fluids is their dry and wet boiling points. The FMVSS (federal motor vehicle safety standard) is who makes the rules for how to classify each type of brake fluid. Obviously having the highest boiling temp seems like it’s the best. But honestly having a high boiling point on a daily driving car that is only driven under normal operating conditions is not necessary, and usually will cost more money too. There are two boiling point measurements, Dry Boiling point means: the temp the fluid will boil without any water/moisture in the fluid. Obviously this is only achievable either right when the fluid is made and is tested at the manufacture, or only right when you flush out your entire brakes system completely, and refill with brand new fluid from an unopened brake fluid container. Now completely draining your whole system usually can only be done with a brake fluid vacuum tool, or thoroughly bleeding your brakes multiple times, and refilling the brake fluid reservoir a few times completely. Some Higher end brake fluid companies will fill their containers with nitrogen to completely eliminate any chance of moisture from the air contaminating the fluid during packaging. Cheaper inferior brake fluid brands will not always do this, so in a way you are kind of already getting brake fluid with a teeny tiny bit of water already in it even before you crack open the seal. Of course all of this is really irrelevant when it comes down to just servicing your regular daily driver car. But if we are talking track/race car then all of this matters. Wet Boiling is what the boiling point of the fluid is once water/moisture is introduced to the fluid, which is really the most important number that you should worry about. The Dry boiling temp is great for manufactures to use to hype their product up and sell you on it having a ridiculously high boiling temp, but in real world conditions the wet boiling point is what matters the most because most likely your fluid will be contaminated in some way or another. Unless you are changing your fluid out after each race, with brand new nitrogen packaged, sealed container, and completely evacuating the old fluid out of the whole system.

Brake_Fluid_Chart

Above is a chart of the minimum standards for each “grade” of brake fluid set by the FMVSS. Yes there are other grades of fluid but as I’m in North America these are the only 4 grades recognized by the U.S. DOT, and also the most commonly used in all types of motor vehicles.

DOT 3 fluid is most commonly used, but also has the lowest dry and wet boiling point. which as I stated above is fine for vehicles under normal operating conditions. Also stated above DOT 3 fluid can absorb up to 1-2% of water each year.

DOT 4 is on its ways to becoming the most predominantly used fluid simply because the it works better in today newer cars with more advanced ABS and traction control systems, which benefit from DOT 4’s lower viscosity. The higher boiling point is also a plus. But also remember the only way to increase the boiling point is to have a higher percent of chemicals that will attract more water, what this means is that you will be absorbing water at a higher rate than DOT 3 fluid.

DOT 5 is a silicone based fluid which doesn’t adsorb water, and doesn’t destroy your cars paint if it gets on it. But before you get too excited you must realize that there are some down falls to the silicone based fluid, and you should do plenty of research before choosing a silicone based fluid. Silicone based fluids might cause certain ABS systems to not function properly. It’s best to check what the car manufacture recommends. Also a silicone based fluid can be up to 4x more in price

DOT 5.1 is going to be the highest minimum boiling point and is made of the same type of chemicals as DOT 3 and DOT 4 fluid.

DOT 3, DOT 4, and DOT 5.1 fluid can all be mixed together however keep in mind that if you add DOT 4 or DOT 5 to any DOT 3 fluid is will pretty much become DOT 3 once it’s all mixed. But it is safe to mix without any adverse reactions to your brakes. You CAN NOT mix DOT 5 with ANY DOT 3, DOT 4, or DOT 5.1 fluid. Now I’m sure you’re thinking why is MOTUL 600 RBF considered DOT 4 still even though the boiling point is higher than even DOT 5.1? Remember that the chart is only what the MINIMUM boiling standards are to for each “grade” of fluid. The main things you are looking for is if it’s a poly/glycol or silicone based fluid, and what the wet boiling point is rated at.

WOW that’s a lot to take in, but the main things to remember are…

  • DOT 3, DOT 4, and DOT 5.1 while all interchangeable have different wet/dry boiling points.
  • Make sure you are changing your brake fluid regularly. approximately every two years for normal driving, if you do a few auto X events a year then maybe every six months,  if you are visiting the track a few times a year its best to do it before each track weekend, and if you are heavily tracking your car its best to do it before each day of each event you are doing.
  • just because your fluid has browned or turned a darker color from when you originally put it in doesn’t mean that its bad. test it to be sure.

 

BRAKE LINES:

This one won’t be so lengthy. Most every car comes with rubber brake lines that connect the calipers to the hard lines coming from the master cylinder. Rubber brake lines are not good because they actually swell when pressure is applied to the brakes, which will naturally make the pedal feel a tiny bit “spongy” (and I say that with some hesitation) because you really have to know what you are trying to feel when I say “spongy.” An auto manufacturer isn’t going to sell you a car with spongy brakes, the car is going to work just fine the way they sell it. However we know from the reading above that there is 800-1200 PSI throughout the brake system and that the brake system is exposed to some extreme heat. Under normal driving the rubber lines are more than capable of handling all this. It’s when we start to demand more from our brakes in intense driving situations. Whether it be on the track, or just aggressively driving. Rubber lines can be the culprit to many issues with the brakes. This includes very spongy pedal when the brake system is getting too hot, the pedal may go all the way to the floor and you won’t build enough pressure to stop within the amount of space/time necessary, and in extreme cases rubber lines can blow out to do overheating fluid and too much pressure being pumped through the system. There is a solution and it comes with great bonuses as well! Stainless steel braided brake lines, these are a great brake upgrade that can be done without having much mechanical skill at all and are a relatively cheap upgrade. All of your brake system unitizes hard lines, and/or stainless steel lines with the exception of the rubber lines that run from the caliper to the hardline and act as the flexible part so the wheels are able to fully cycle the suspension and the steering can turn with out brake lines fatiguing/breaking. Cars don’t usually come with stainless steel lines just do to cost for the manufactures to put them on 1 million of their cars and the rubber lines will suffice. The Benefits you will get from installing these is a firmer pedal due to the rubber lines not swelling under pressure, and will give you peace of mind under extreme braking conditions that your brakes wont fail. If you are in any way serious about tracking your car this is a must upgrade.

BRAKE BOOSTER:

Up until the 60s and 70’s the brake booster wasn’t even a common thing on automobiles. For some of us that are younger it’s hard to even imagine what it would be like not having power brakes. A boosters job is to take vacuum pressure from the engine to help multiply the amount of pressure that your foot is applying to the pedal therefor increasing the pressure in the brake system. It’s what allows us to lightly press the brake pedal yet still slow the car down quickly. Another way to think about this is… non booster cars have a pedal ratio of 1:1 meaning if you put 100 lbs. of pressure on the pedal then you will get 100 psi of pressure to the brake system, and if you take a vehicle WITH a booster and a pedal ratio of 7:1 with a 1 inch master cylinder and the same 100lbs of “manual pressure” applied with the foot the brake system will develop 891psi. The brake boosters only job is helping to amplify the amount of pressure in the brake system and keeping you from getting a calf cramp. A larger brake booster will only increase the pressure to the master cylinder linearly. It allows for people to have to put less effort into pressing the brakes for the car to stop as fast as if you had a smaller booster applying the same pressure.  Still this is on such a small-scale for Hondas that it’s really irrelevant to upgrade boosters. Please keep in mind this is a very basic description of what the booster does and there are also other factors to take into consideration. Size of master cylinder is a huge one that can affect how much pressure is delivered to the brake system, and pedal feel. Different sized brake boosters can also determine how much brake pedal modulation you get. simply put how much movement you pedal will have before the brakes are applied, and how touchy the brakes are. Let’s jump to into Hondas real quick. On an EG chassis there are a few different sized boosters for the different sized brakes, rear discs, and drums, and each one having a different sized master cylinder. But on the EK chassis every booster was the same size for all models even the EM1 civic SI with rear discs. The only thing that was changed on the EK chassis was the master cylinder. There is a big misconception in the world of boosters, and what people think you should have on your car. Honestly in my opinion it doesn’t really matter because its only adjusting the amount of pedal input and throw which is all subjective. Some people like their brakes touchy or some like them with lots of modulation. Again there are many different scenarios that can affect all of this. If you are upgrading you brakes on a Honda or any make of vehicle and you are using OEM components to upgrade the brake system most likely you are going to be OK and really shouldn’t have to worry too much about math. If you are building a custom brake system then all of this math is very important.

We can talk briefly about the world of brake booster deletes. Largely these are synonymous with engine bay tucking, or to gain clearance for large turbo setups, and most people don’t like how the pedal feels when they delete the booster. It’s mainly because you have effectively taken the power aspect out of the brakes and it has become 100% manual. The reason that so many people aren’t happy with brake booster delete kits is because they are just removing the booster but leaving the pedal ratio the same as it was with the booster so you are having to press extremely hard on the pedal to get the same amount of braking as when you had the booster. In terms of Honda’s there is a company in Australia called Honed Developments who are really doing some neat stuff aimed at improving suspension and braking for track specific Honda’s. They have developed a brake booster delete kit that is proving to be worthwhile upgrade for people who want to get the most out of the braking with their Honda/Acura.  Their kit relocates the mounting point of the rod that comes of the booster and connects to the brake pedal thus allowing you to still achieve a 6:1 pedal ratio and a completely linear braking pedal feel which is much better in terms of hard braking because you are able to get the brakes to act exactly how you want them to act without relying engine vacuum pressure that under racing circumstances is constantly changing. Having a brake booster kind of gives you a false sense of what the brakes are doing because the input on the pedal isn’t direct so to say. I’m still not a 100% believer in giving up my booster nor have I tried their booster delete kit. But I am very interested in trying a car out that has it just to see how it feels, from hearing what some people have said about it I think that Honed is really on to something and once we lose the impression of “all booster deletes make your brake pedal very hard” we will see a boom in their kit.

For anyone trying to upgrade their brakes on their Honda/Acura please keep in mind that  on 5th get civics ABS and NON ABS boosters and master cylinders are not interchangeable. However if you change booth the booster and master cylinder out for both ABS or NON ABS ones they will work together. For instance if your car came without ABS then you can switch to an ABS booster and master cylinder and it will work. or vice versa. but you cannot use a NON ABS booster with an ABS master cylinder, or an ABS booster with a NON ABS master cylinder. this is where a lot of people get confused. the rod from the coming out of the booster where the master cylinder bolts on is longer/shorter on NON ABS and ABS ones, and the depth of the hole on the master that the rod slides into when bolted up is deeper/shallower on NON ABS and ABS master cylinders.

Remember if your booster is bad your brake pedal will be firm. This is because the vacuum assist is no longer assisting in creating pressure and is effectively making your brake system “manual.” If your master cylinders bad your brake pedal will slowly sink to the floor while stopped at a light, or in traffic. This is because the master cylinder can’t keep constant pressure due to a bad seal therefor letting the pressure bleed off as opposed to staying constant. Lastly its more rare but still possible for your check valve in you booster vacuum line to be bad, which is easy to check, and easy to fix.

MASTER CYLINDER:

The master cylinder is full of a lot of misinformation! starting with the fact that a larger one will increase the pressure to the calipers… this is WRONG. Here is the truth, and I’m sure some of you don’t want to hear it. First let’s discuss the definition of a master cylinder. A master cylinder is used to convert force from the brake pedal into the hydraulic pressure that operates the brake calipers. The amount of pressure generated is a function of the force being applied, divided by the master cylinder bore area. A 1” master cylinder has a bore area of .785” inches squared. For every hundred pounds of force applied to the master cylinder piston by the pedal push-rod or balance bar, that master cylinder will generate pressure equal to 100 divided by .785 or 127.4 PSI. By calculating the area in inches squared (bore x bore x .785”) for any master cylinder size, you can calculate how much pressure change would be affected by a bore size change.(the math was taken from Joes racing)

a SMALLER master cylinder bore size will INCREASE LINE PRESSURE at the expense of LONGER PEDAL TRAVEL. A LARGER master cylinder bore size will give a FIRMER pedal at the expense of LOWER LINE PRESSURE. Let that sink in for a little. Higher line pressure = higher clamping force. I know this is hard for some of you to believe, but the firmer pedal feel you get from a larger master cylinder doesn’t equal more pressure to the caliper. While a larger master cylinder creates a larger displacement, it takes more force to create the same pressure as a smaller bore. While a larger master cylinder will take up system slack with less pedal stroke, it will take more force to create the same system pressure. The result after adding the larger master cylinder is a harder pedal which needs much more pedal pressure to create the same amount of braking force. For instance, moving from a 3/4″ master cylinder to a 1″ requires 77.7% more force on the push rod. But upgrading to a larger master cylinder is a must when upgrading to larger calipers with larger pistons because it takes more fluid to push the pistons, therefor you need a larger master that can move more fluid. If you had a tiny master cylinder but upgraded to larger calipers you might need to push the brake pedal almost all the way to the floor to get the brakes to fully work, since more fluid is being displaced. Let’s look at this chart below to see how little we are talking about when you upgrade your master. Most civic/integras are 13/16, 7/8, 15/16, and 1 inch.

ruler-fraction-measurements

As you can see there isn’t much difference, so a little upgrade will make a big difference in applied braking force and brake system pressure. Generally speaking when you upgrade calipers (with bigger, or more pistons) they demand more fluid to make them work. Upgrading to a larger master cylinder helps to move that fluid with out so much throw in the pedal. There is a tremendous amount more to know about the master cylinder and how it can affect the braking system. For most people this information is all that is needed as they will never upgrade their brakes past this level. With most Honda owners we just interchange oem parts from other cars to make a more robust braking system. This also works well because Honda’s are very light.

Let’s dive into Honda’s a little more. Currently on my cars I’m running Spoon twin block calipers on my EG which are a four piston caliper, so therefor I’m running a 1 inch master cylinder from an NSX.

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I did have to change out one line to a custom stainless steel one that runs from the master to the prop valve since the outlets on the brake master cylinder are 10/12mm not like a regular civic or Integra one with 10/10mm. Im also running an ABS booster because the NSX came with ABS. so remember I must use ABS master and ABS booster, or NON ABS master and NON ABS booster.

On my EK I’m running NSX calipers with a 98 GSR 1 inch master because the NSX calipers are two piston.

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On EK chassis I feel like its easier to upgrade the master cylinder since the brake lines come out the same side of the master as most Integras, and all EK chassis. where as upgrading the EG master requires a bit more hunting.

Remember that if your brake pedal is losing pressure while sitting at a stoplight its most likely your master cylinder that needs to be replaced.

PROPORTIONING VALVE:

Here is where the idea for this whole article came to mind, I was experiencing some leaking brake fluid dripping on to my rear motor mount, and after a few days trying to diagnose the leak I narrowed it down to the prop valve. I’m not mad at it, It’s given me 12 years of great service and I’m sure it was just it’s time to go. The only problem was sourcing a new one since Honda has discontinued this item. I was forced to pick up a used one, and luckily for me a friend had one lying around that he could vouch for being good. It comes from a DA Integra so I have to remove the safety bolts and switch the mounting brackets from the DA one to the EG one.

You can see this is what it looks like when I got it, and you can see the finger is pointing to where it says 40/40

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it turns out it was leaking from the rubber plug, and apparently this is pretty common under extreme conditions.

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Here is what it looks like all taken apart. Note that to change the brackets you must remove the safety torx bolts which can be a bit of a challenge. I ended up striping one so I took an angle grinder with a cut off wheel and carefully grinded a slit in the bolt so that I could just use a big flat head screw driver to remove it.

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Just make sure you don’t re-use the safety bolts that you have just taken out. I just run new bolts .

Here is the difference in the two brackets. the EG one is on the left and the DA on the right

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Any time you are doing brake stuff you should be using the correct wrench to help avoid rounding off the fittings. As you can see above the finger is pointing to the “Flare nut wrench” this is the one you should be using. the regular open end wrench will only flex and round off the fittings for any brake line. the only time you can use the wrench on top is when bleeding the brakes and you use the close end to go on the bleeder screw. NEVER USE THE OPEN END SIDE!

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Here is the prop valve on the car, me removing it, and then it removed. Yes some fluid is going to leak so try to be quick while you swap over the brackets. *pro tip have the DA bracket already removed from the 40/40 valve you are going to be using, so all you have to do is remove the eg bracket off the old/bad prop valve. Don’t worry though as long as you have left the cap on the fluid reservoir the fluid won’t leak out too quickly. There is no bench bleeding or prep that needs to be done when installing the new prop valve, however you will need to thoroughly bleed the brakes at all four corners.

What is the purpose of the proportioning valve? The proportioning valve typically connects the master cylinder to the rest of the braking system, but sometimes it is independent of the cylinder. This valve is necessary for optimizing front-to-rear bias, also referred to as brake balance. It is a spring-loaded component that activates when fluid pressure builds when you step on the brake pedal. Then, the valve’s plunger unseats and fluid rushes into the calibrated range. Once this happens, the spring gets compressed and the plunger blocks the fluid from passing through. Even pressure distribution among the front and rear of your vehicle is important for safe and reliable braking performance. There is only subjective answers when it comes to brake set up all things listed here play a role in the overall braking of our cars, and the prop valve merely is the bias for the brakes. Your pad, caliper, disc size, and tire compound are all variables when it comes to your brake system working well. Like I’ve said a million times, what set up works for you might not work for someone else. driving styles, and modifications can all alter the outcome of brake modifications. Just putting the largest brakes you can fit on to your car isn’t always the best thing, this will only cause your brakes to lock up too easily if your car is really light. But if you have proper sized master cylinder and prop valve set up it would be possible for it to work, but the question is why would you want such a large brake set up?

Using the proper sized proportion valve is important because let’s say you’re doing a rear disc conversion (removing your drums and running discs) the drum shoe (what the pad is called that is inside the drum) is actually a few MM away from the drum so more fluid needs to be sent to the rear drums. With discs the pad will actually barely skim the rotor as the car rolls along, so there is not much fluid that is needed to make the pad contact the rotor. If you leave the prop valve for the rear drum on after you put on the discs there is more likely a chance of the rear brakes locking up first which is not a good thing. You always want the front to lock up before the rear does. A lot of people don’t think you need to change out the prop valve, but this is where the misinformation starts spreading like a cancer. Yes you technically can drive your car with a prop valve meant for drums if you have installed discs… BUT, the people who say they don’t have any issues are people that are not actually using their brakes to the fullest potential, and are most likely people that just want the looks of rear discs and are only driving their car gingerly around from show to show. Brake pad compound and choice also plays a big role in brake bias, so choosing the correct pad compound for the front and rear will greatly affect how the brakes will lock up. The main reason to switch out for a 40/40 is to maintain OEM brake bias (this only applies to Honda’s) when doing a rear disc conversion. For Hondas there are many different options of proportion valves. for 5th gen civics it’s usually 30/30, 40/30, 40/40 there are some other ones involving 35 but seem to be a little less common. then 6th gen civics do not have a stamp on the prop valve so it’s kind of tricky figuring out which one is which. Honestly when I did the rear discs on my EK I just ordered a brand new EM1 (civic SI) prop valve from Honda, this took all the guess-work out of sourcing one form the junkyard. Even now I still see people saying that all EK prop valves are the same, and people go back and forth arguing about it. I can’t confirm nor deny if they are all the same or not, so I just ordered the part number that Honda calls for the EM1 prop valve since it for sure only comes with rear discs. maybe you can use a dx, lx, cx, or ex, but the fact of the matter is I sleep well at night knowing that I have the one brand new from Honda with matching part number for the EM1 chassis. If you are really taking your car to the limits getting an aftermarket proportioning valve with adjustable brake bias is the way to go. This can help perfectly dial in the brakes so you are able to utilize the whole braking system to it’s fullest potential with out any wheel lock up. This modification is really best left to a more experienced racer, someone that will know how to diagnose what the car is doing on track and know what adjustments to make.

For Honda’s the brake recipe has already been tested a million different ways, you don’t need to reinvent anything. EX/SI/GSR front and rear discs, the matching prop vale, booster, and master cylinder for which ever you are going to use (if you can’t use the master from the car to match just find one closest to the same size off another chassis), some good brake fluid with a higher wet boiling point, stainless steel lines, and a good pad choice. You don’t even need drilled or slotted rotors, a lot of people are really fast with blank rotors. Some people just use autozone rotors, because the rotor is a consumable and will always get worn out really quick when using more aggressive pads, any rotor will eventually start to crack, and warp it’s just a byproduct of trying to being fast. So rather than spend hundreds on fancy rotors that will only get ruined they opt for money-saving cheaper rotors. If that set up isn’t working for you then you can go to the next level and switch to 2007 base model mini cooper rotors (assuming you are 4 lug, if you are five lug just use type r rotors), and type R, NA1, or spoon calipers. But it should be noted that with the 4 piston calipers you should probably switch to a 1 inch master cylinder. Both of these setups are tried and true and many people are very fast on these setups. Some people talk about going to a larger rear rotor size like a type r, but most people argue that it’s over kill for a light weight civic. Yes there are many other potential set ups to go with, and even bigger ones too. but you really have to ask yourself if it’s really necessary for you. Yes it may look really cool, but you’ll look pretty stupid if you have all that bling in brakes but aren’t really that fast. Just pads, rotors, and fluid can drastically change the dynamic of your whole braking system, so keep this is mind before you start going crazy with huge brake upgrade. Remember that heat kills so brake cooling is also another great investment, vented rotors, ducting, and air guides can all be very beneficial. OK, OK enough about proportion valves that one got a little out of control.

PADS:

I’m not really going to touch too much on pads, as most people are very loyal to a certain brand or style of pad and will fight to the death about how superior their pad is. The most important thing for getting a pad to work to its fullest potential is BEDDING in the pad properly if this is not done correctly it can cause all kinds of issues with you brakes. This topic again is best left up to the manufactures guidance as many manufactures ask you to BED-IN the pads in different ways. It’s best that you look up the instructions for your specific brand and pad model. Different pads also have different characteristics, so whether you want good initial bite, or more ability to modulate the pedal all has to do with pad compounds. Some will have to be warmed up to work best, some will work good cold, some pads are extra aggressive and will wear out your rotors quickly, other can wear out quicker than your rotors, and finally some are high dust, and some are low dust. below is some cheat sheet charts ive taken from EDGE AUTOSPORT to help give you a basic guide on what pad you should be looking for. yes there are very many other pads out there, but you can use the ones listed below to reference for comparisons to those other brands. ( by no means am I saying that the pads listed below are the ones you should use, I know there are other brands out there that may be better. The charts are only listed as a guide to visualize the different stages of each pad)

Pad choice can drastically alter the characteristics of you brake system, and is easily one of the most noticeable upgrades in the brake system. I have personally used HP+ pads on track conditions and experienced some fade and was not happy. The next track day I upgraded to the project mu club racer pads, which I liked better overall. I didn’t experience any fade with them, the pedal modulation was awesome, and stopping power was consistent. However they do take a lap or two to get up to operating temp, so be cautious on your first lap out (as you should be anyway since most likely your tires are cold). I also have some friends running carbotech XP10/XP8 pads and they LOVE them. I myself am thinking of trying these out for my next pad just to see what all the hype is about. Just for shits and giggles here is the carbotech chart for suggested brake pad usage.

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Since Honda’s aren’t usually too heavy and don’t have high horse power. Choosing any pad above the xp10 will only be overkill and might cause your brakes to lock up too easily. Pad selection much like putting too big of brakes on your car can have adverse reactions and decrease brake performance so be careful when choosing. Its best to actually talk to people at a track day and see what they are running and listen to their real world experience with the pad they have chosen, don’t be quick to just listen to people online as you have no proof of how hard they are actually driving.

ROTORS:

Upgrading to a larger rotor will increase the surface area for the caliper to clamp on thus slowing the car down more. But like everything that we have talked about, too big isn’t always best and can cause wheels to lock under braking. All OEM front rotors for Honda’s and pretty much every car made come vented, this helps with cooling the front rotors since the front is a large portion of the cars braking. When you upgrade to different aftermarket rotors usually the companies will improve the “vented” cooling veins to help aid in keeping the brakes cool. High end brake rotors utilize highly tested and/or patented designs that are very effective at dispersing heat, while stock rotors are much less able to do so.  When performance brake rotors are engineered at the factory, they are done so to maximize surface area and modify air exchange to some degree. A well designed high performance brake rotor will be engineered to work much like a heat exchanger, and serve to evenly disperse heat across the brake rotor in a highly efficient manner. A stock brake rotor, on the other hand, will have a less of a focus on increasing the heat exchange rate of the rotor itself, and a greater focus on lowering the overall cost of manufacturing the rotor.  The main disadvantage a stock rotor has over a high performance or racing style rotor is lack of surface area built in to it.  Because brake rotor plates are much closer together in stock rotors, as opposed to a racing style of rotor, and without a fancy vein design, air circulation is cut down immensely. You can expect the cooling capacity on a stock or poorly designed brake rotor to be sub par overall, so keep this in mind when deciding on more aggressive brake pads or caliper upgrades later on to further increase braking performance. The generic photos below show the three most common type’s of veins. The other shows the difference between OEM rotors and aftermarket ones (in general).

 

STRAIGHT VEIN: This is the most common type you will find.  This style of brake rotor has the lowest cooling capacity, but it is the lightest overall due to its reduced amount of material content.

VARIABLE VEIN: This brake rotor style is similar to the straight vein rotor design, but comes with a variation in vein pattern to disturb air flow across the brake rotor plates.  This air turbulence that is created aids the dispersing of heat at an increased rate.

PILLAR VEIN: Brake rotors with the pillar vein rotor design are similar to variable vane rotors, but have a more predictable pattern and are not generally patented.

Each company tries to make their own secret style of vein to help get an edge over another company. But the fact is that any aftermarket rotor is going to increase cooling in some way and save some weight in rotational mass. We all should know that rotational weight weighs more than static weight, can make the car more responsive under acceleration and braking. there is a few different formulas out there, but just to give you a rough idea: 1lb. of rotational weight is equal to somewhere between 5-10lbs. of static weight. Of course many other factors go into this, but I just wanted to make you aware of just how important small weight savings in rotational weight can be. High performance brake rotors made for high performance or racing vehicles typically have a curved vein designs. Curved brake rotor designs are not only great at cooling the brake rotor efficiently, but aid to increase the strength and reliability of the rotors.  The veins in these designs deliver the greatest amount of brake rotor surface area thereby acting much like a heat sink. Due to the curved vein design, air is now semi-pressurized before it leaves the surface of the rotor, thereby leveling out the heat signature of the brake rotor. An uneven brake rotor heat distribution pattern can lead to cracking, which drilled rotors are notorious for. This is why sometimes you see peoples slotted rotors pointing one direction and sometimes another person will have their slotted rotors pointing in the opposite direction. This is because the manufacturer has specified the Left and Right rotor so the cooling veins will properly function. I hate it when people say someone has their rotors on backwards. There is a lot of science in rotors, managing heat, and cooling. Please don’t by cheap eBay rotors, they are made of inferior metals and most times dont even meet minimum safety requirements since they are technically “for off road use only” meaning it does not have to be DOT certified. This goes for the whole braking system… You shouldn’t skimp on any part because it only takes one part to fail for you to destroy your whole car, forget about your life I could care less about that. I just don’t want to see another totaled Honda.

  • BLANK ROTORS: Blank rotors provide more than enough stopping power under normal driving conditions. That’s why 99.9% of new cars still come with them from the factory. They provide the most surface area vs. drilled or slotted rotors and therefore are very effective at acting as a heat-sink, which is exactly what a brake rotor was designed to do. They’re also not as prone to cracking under extreme use like drilled rotors can be. The absence of slots or drill holes allows smooth rotors to maintain maximum structural integrity, making them good for moderate track use.
  • SLOTTED ROTORS: have grooves cut along the face of the rotor where the pad makes contact. This is because under repeated heavy braking, as the temperature of your brake system increases, a layer of gas and dust forms between the pad and rotor from the material transfer caused by friction. The slots in the rotor allow an escape route for the built-up gases. This allows more of the brake pad’s surface area to contact the rotor, resulting in better pad bite and more consistent stops. Also, this increased surface contact results in a higher coefficient of friction, so you’re actually using less energy to slow your vehicle the same amount. The venting provided by slotted rotors is one of the main ways to combat brake fade and maintain consistent stopping power.
  • DRILLED ROTORS: keep your brakes cooler. In the early days of racing, drilled rotors were an effective way of venting the layer of gas and dust that inevitably builds up between asbestos brake pads and the rotor under repeated, hard braking. However, as technology and brake pad materials have progressed, outgassing has become less and less of an issue. These days, while they still look great and perform well, the drill holes are more for aesthetic reasons than anything else. For performance driving, slotted rotors have become the preferred choice because cross drilled rotors are more prone to stress cracking under extreme use. Just take a look through the spokes on the wheel of any modern race car ( that isn’t a carbon rotor) there won’t be a drilled rotor in sight. On the street where the temperatures of your brakes never even come close to the levels they do on the track. So the venting properties of drilled rotors offer the added benefits of keeping temperatures down under normal driving for prolonged pad life, as well as improved wet-weather performance by allowing water to escape the rotor’s surface, increasing initial pad bite.
  • DRILLED and SLOTTED ROTORS: will give you the looks and functionality of both drilled rotors and slotted rotors combined. While still not ideal for the abuse they would suffer on a racetrack (the drill holes being prone to stress-cracking), one of the places drilled & slotted rotors shine is on heavy vehicles towing heavy loads. The heavier the vehicle, the more energy is needed to slow it to a safe and reliable stop. Brakes convert kinetic energy into heat energy, and heavier vehicles invariably generate more heat in their braking systems. So a rotor that runs cooler (drilled) combined with one that maintains a clean contact surface between itself and the brake pad (slotted), when not pushed beyond its thermal threshold, can provide an extra bit of security and durability. Remember, the name of the game is maintaining consistent stopping power every time you hit the brakes. If you’ve ever towed a fully loaded trailer down a mountain pass, you know the terrifying feeling of brake fade. A set of cross-drilled and slotted rotors can give you additional peace of mind by keeping temperatures down and the rotor face clean.

CALIPERS:

I not going to get too into calipers, anyone that is upgrading their Honda won’t necessarily need to put high performance calipers on their cars. Im just going to briefly talk about them so you are aware of what they can do for you. In a high performance braking system, A brake caliper that is made of strong materials will be resistant to flex or torsion, and multiple pistons will create more points of contacts on the brake pads.  This combination of features will increase clamping force of the brake caliper over stock, and will do so without any down sides.  It is important to note however that upgraded brake pads and rotors should also be done at the same time because these parts help dissipate the heat created by the upgraded caliper, and will add to the braking stopping force gain. In terms of Honda’s, upgrading to a multi pistons caliper isn’t necessary. There are plenty of fast guys on OEM ITR calipers and ITR sized rotors. As you’ve just read there is a lot more that goes into setting up the perfect braking system with all parts working in unison. While the ASR/AP racing  BBK is awesome, and SPOON calipers are quintessential in achieving that ultimate look. They are really over kill unless you are really, really, REALLY tying to set fast lap times. as stated above you’ll do just fine with some OEM Honda stuff. There are two main types of brake calipers, floating brake calipers and fixed brake calipers.  A floating brake caliper will have only one brake piston in operation on one side of the caliper arm.  A fixed brake caliper will have caliper pistons on both arms of the braking caliper to apply pressure to both ends of the rotor at the same time. These caliper pistons only serve to apply pressure to the brake pads, however more pistons mean more pressure applied. Due to the nature of how hydraulic systems work, more piston surface area or pad surface applied to the brake rotor is not what increases clamping power or braking stopping force. What does increase the braking stopping force however is the use of multiple pistons in a brake caliper and or using larger diameter caliper pistons. More pistons and or larger diameter pistons result in a multiplication of mechanical force.  As stated above in the master cylinder section if you increase the size of piston, or number of pistons you will need a larger master cylinder to increase hydraulic fluid flow to the caliper. Otherwise your brake calipers won’t clamp hard enough, the pedal throw will be all wacky, or you won’t even be able to evacuate all the air out of the system when bleeding.

BRAKE BLEEDING:

Lots of theories here for sure, I’m just going to go over what I do on any car I bleed brakes on. Whether it be, truck, car, daily, race, family, sedan, coupe, or any other rendition of an automobile. Im also going to start off with the age old adage… Theres more than one way to skin a cat! My way works for me, but your way may work for you, and for those that don’t have a way mine will work just fine for you.

The best way to achieve completely bled brakes is to do all four corners, this insures there is no trapped air bubbles. Start by braking the lug nuts loose, jacking the car up on to four jacks stands one at each corner of the car, and remove the wheels. You can either do it with the E-brake on or off, This is also a hot topic area so ill just tell you that the manual locking of the rear brakes due to the E-brake being on has already clamped the pads to the rotor. The piston can still move when you pump the brakes, therefor still allowing you to evacuate all the air. Ive done it both ways and it works either way. OK you are going to need a friend to help you. Have your friend sit in the drivers seat and he/she is going to pump the brakes for you while you open the bleeder screw to allow the trapped air to escape. But first! make yourself a brake fluid catching container to keep this job less messy. You’ll want to get some clear tubing (so you can see i there are still bubbles coming out) that will fit snuggly over your bleeder screw tight enough to not allow fluid to escape when you open the bleeder screw. Get a few feet of the tubing, then take a water bottle and drill a hole in the cap and slide the tubing into the water bottle (remember to make the hole a little bit bigger than the tubing, you don’t want the rubber tubing to create an air tight seal with the hole in the cap because you are trying to bleed air out of the caliper and that air will pressurize the water bottle and could create some fizzy leaks) here is my set up._DSC6805

Big, sturdy, stable, don’t use one of those tiny 12 oz water bottles its way to flimsy and will fall all over the place leaking brake fluid all over and you’ll just get angry.

Next you are going to start bleeding at the caliper farthest away from the master, and  end at the caliper closet to the master. Sometimes you’ll need to follow the lines under the car because what caliper seems the farthest away might not actually be the farthest away in terms of how far fluid has to travel to get to it. But usually on a LHD car its right rear, left rear, right front, and then ending at front left.

_DSC6818

Heres how I hook everything up, and if you notice im starting on the right rear. Now you are going to have your helper pump the pedal 3x then hold strong pressure on it, open the bleeder about 3/4 turn the pedal should rapidly press all the way to the floor (must go all the way to the floor) make sure your helper holds it there until you have closed the bleeder all the way. Once you have closed it they can let off the brake pedal (if the pedal is stuck to the floor its ok, just have them pull it back) now I do this 3x then move on to the next caliper which is usually the left rear. While I’m moving sides I check the fluid level in the reservoir to make sure it doesn’t get too low. (if the fluid runs out completely you are going to have to bench bleed the master, which is something totally different and requires a separate how to article) just don’t let the fluid get that low, if you check after each caliper you do then you’ll be fine. Now I do the same thing, have the helper pump 3x then hold strong pressure, crack open bleeder, make sure pedal goes all the way to the floor, close bleeder, then release foot and bring pedal back to the top. do that a total of 3x for that side. Now on to the front. If you have an OEM caliper with only one bleeder screw you are going to do it the same way as you did the rear. pump 3x, hold constant pressure, open bleeder, push pedal to the floor, close bleeder, bring pedal back to top. do that 3x then on to the last caliper and repeat the same as above. Now I have spoon calipers which have two bleeder screws per caliper. If you have two bleeder screws per caliper then you are goin to start with the outside bleeder screw

_DSC6809_DSC6814

same thing as all the other calipers. pump 3x, hold firm pedal pressure, open bleeder screw, make sure pedal got to the floor, close bleeder screw, bring pedal back to top. do that 3x just like all the other calipers. Now you’re going to move to the inside bleeder screw.

_DSC6812

and do the same thing as you did for the outside bleeder. please don’t make me re type it again. I’m sure you get the point. You also want to make sure the fluid reservoir cap is off just to make sure there is no vacuum in the system that would cause air to stay trapped in.

_DSC6824_DSC6820

Make sure you are remembering to keep the brake fluid level topped off when you are switching calipers. I usually do this whole sequence 3x times around the whole car. but you can stop after one or two times if you’re happy with your brake pedal feel.and don’t forget to put the cap back on the reservoir when you’re all done. take some brake clean and spray it around the bleeder screw areas just to make sure you don’t leave any brake fluid on any painted calipers, or get any brake fluid on your rotor surface._DSC6819

 

Thanks so much for reading this incredibly long article. Again I don’t want to really tell you what the best brake set up is for you, or start any arguments about what’s better. I just wanted to lay out in detail what every part of the brake system does and then let you decide what’s best for you and your car. I did list what brakes I have on my car, just for your reference to see my setups. Please keep in mind the only reason I have the NSX calipers on the EK is because they were once on the EG but when I upgraded to the spoon caliper I just kept the NSX ones so they were literally just laying around in my garage, and I happened to have some old Mini Cooper rotors that I had taken off my EG as well, AND I had some old pads too. so yes it is overkill but its just spare parts I had. I went to the junkyard and got the GSR 1 inch master for 20 bucks also. The most expensive part of  the upgrade way the EM1 Prop valve that i orders brand new from Honda.

Another thing to remember is that what set up works good for some doesn’t work good for others, and there isn’t really a brake setup that is the “best.” while there is good bases to start with, it will take you dialing it in based on your driving skill/style. Take what knowledge you have learned from this article and make educated decisions yourself about brake setups. Im telling you that if you pay attention to peoples cars that actually get used on track you’ll be surprised by some setups, what I mean by that is how simple they actually are. Having bling bling brakes is cool and gets the fanboys all wet, but if you can’t back all that expensive hardware up then the real enthusiast will see right through you.

Please don’t hesitate to comment, dm, or email me any questions you have regarding brake set ups. I’m by no means an expert but I do have good knowledge and experience. and please if you like what you read… please share it, or tag someone so they can read about it.

 

 

 

 

 

 

 

8 thoughts on “10k words about brakes! everything you need to know about every part of your brake system.

  1. So I fell onto the change/don’t change prop valve rabbit hole when I did a gsr brake swap with 15/16mc and poterfield pads up front and stock in back on my 94cx hatch. Ended up not changing it before I went to track and it worked well at sow with d15b. But after reading your article it got me thinking. Should I go 40/40 prop valve? I have a 30/30 one now. Also pedal is a lot better than stock but it could be more firm.

    1. If the 30/30 works for you now and you’re not really experiencing any locking of the rear before the front I wouldn’t change it. What fluid are you running? Changing to a more higher end fluid. Motul, stoptech, project mu etc… can actually increase pedal stiffness. Also if you don’t have stainless lines that will help improve pedal feel as well. And lastly brake booster size can affect it too. Also tire compound can dictate how hard your brakes can work. Meaning they can lock up easier if you’re running street tires due to less grip. Or they won’t lock up as easy if you’re running r compound tires. I hope this helps. Feel free to ask any other questions. And please understand it’s sort of hard to diagnose/dial brakes just through some text.

      1. No locking in rear.
        Running ate Amber brake fluid
        Stainless lines
        Stock booster
        Federal rsrr 205/50 15
        Brakes can lock if I slam on them full force application. Fronts lock first.
        The pedal is just softer than I’m used
        to as I prefer a more firm pedal.
        I did however forget to mention I upgraded to a b18c since my last track event.

        1. Well it sounds like you got a good setup. All you’re really missing is a prop valve and bigger booster. So I would give the prop valve a try and see if that gets your pedal feel how you like it. But again pedal feel is all subjective. But I too like a stiff pedal and I was running the same set up you have now for a while expect I had a larger booster and the 40/40. Let me know how it goes. Sorry I can’t really be of more help

  2. No that helps a lot thx man. I was at Chuckwalla too a few weeks ago. But unfortunately I was hurt I was dude going around in crutches if you happend see me lol. But hope to see at next VTEC club event or track day!

    1. I’m glad I can help. No I wasn’t there, I’m located in Las Vegas so it’s not to often I get down there. We were actually trying to make it down to chuck next weekend but I don’t think my friends suspension parts will be here in time for us to get them installed and all realigned. He’s the one with the red s2000 featured on the site.

    1. No worries. Yea he makes the trek down there more often than I do. We usually do events up here like PCA at spring mountain motorsports,SCCA and lvms outside road course, and vtec club at lvms outside road course.

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