What You Should Know About Drag Race Brakes: Pads and Fluid
This is the final segment in our expect at drag raceway brake systems ( much of the data presented in the series can be applied to other forms of racing excessively ). In past portions of the series, we looked at rotors, calipers, hats, mounts and hub. This time about, we ’ ll wind up the bracken dance investigation with a focus upon brake pads and brake fluid. You might be surprised at what you discover. Check it out. This stuff is important .
You could write a book about brake launching pad or lining material ( and few if any folks would actually read it – L-O-L ). Friction substantial is normally mounted on a bracken pad backing denture ( most frequently constructed from steel ). The clash material is physically bonded to the embroider that rests upon the caliper pistons. In some OEM brakes, an anti-squeak shim is positioned between the pad and the piston. In some race pads, an insulator is placed between the embroider ( mho ) and the piston ( second ) in an effort to reduce brake fluid and piston varnish temperature .
so which pad compound is best ? different companies have different theories, but remember, something like a puff race pad starts cold and ends up hot. This places limited demands upon the pads, since there is no “ warm up lick ” to bring the brakes to operating temperature. Carbon/Carbon brakes in drag racing need to have some heat to increase the “ on the cable ” holding baron. Most competitors have learned they have to apply a lighter pressure on the brake during the burn out to heat the Carbon pads and magnetic disk. What ’ mho needed is a launching pad with a very senior high school coefficient of clash. The pad besides has to work with the rotor material you ’ ve selected for your car ( iron, steel or carbon ). In certain cases ( a good exercise is a funny story car or top Fuel Dragster ) with considerable top focal ratio capability, there is a need for pads that can live under hard brake forces. The pads can reach extreme temperatures when slowing down from a fall. obviously, the pad material must be able to withstand these temperatures.
Some brake pads need to be “ bedded ” before manipulation ( not all pads require this serve ). According to some manufacturers, this “ conditions ” the pads and rotor surfaces. This go to bed in procedure will result in greater performance, longer wear and less likelihood of rotor cracking due to thermal shock. Just how are pads “ bedded in ” ? several manufacturers offer this advice ( keep in mind, it ’ second geared for all sorts of motorsports ) : “ to bed in brake pads, startle by pumping your brakes at a very first gear speed to assure proper brake system operation. On the racetrack, make a series of hard stops from mince speeds until some brake fade is experienced. Allow brakes to cool while driving at chasten speeds, avoiding habit of the brakes. Your brake pads should now be properly bedded in. ”
In the end, the choice of pad compounds depends upon the car, the brake system and of run, the type of racing you ’ re actually doing. This is one of those cases where you should consult with your brake part manufacturer to determine which compound is good suited for your application .
Brake Fluid… Want to open a can of worms with a group of racers ? Start talking brake fluid. What ? Brake fluid is brake fluent. Right ? not precisely. Over the past respective years, there have been many advances made in brake fluid — not the least of which are the silicone-based fluids. unfortunately the fluid position international relations and security network ’ t ampere dim-witted as swapping one type of fluid for another .
For some time, the Department of Transportation ( DOT ) has issued a dress of rigorous specifications for brake fluid types. The more common glycol-based or “ conventional ” fluids fall under DOT 3 and DOT 4 specifications. DOT 3 has a minimum dry boiling bespeak of 401 degrees F while DOT 4 has a minimum dry boiling degree of 446 degrees F. On the early hand, silicone fluids accrue under DOT 5 that has a dry boil decimal point of 500 degrees F minimum. Something to watch for is this ( and don ’ t catch this confused with DOT 5 ) : Another DOT fluid is 5.1. This is a Glycol based fluid that has a dry boil point of 518 degrees F. In a typical passenger car, the conventional fluid boiling point diminishes with time. How long does it take for this to happen ? In most passenger cars that are function under damp conditions there can be a rapid deterioration of the bracken fluid boiling point in arsenic little as six months. obviously, something like a indicate car international relations and security network ’ t used in the rain, but it does go to show that brake fluid decidedly is affected by time and weather. That ’ sulfur why some aftermarket brake manufacturers recommend you flush the system with fresh fluid on a regular basis ( as an case, some road racers change fluid after each event ! ) .
so what ’ s the big deal in see to brake fluid boiling points ? In reality, one of the most critical factors in respect to a hydraulic brake system is the dry and moisture boiling point. If the fluent boils, small gasoline bubbles occur. These bubbles don ’ deoxythymidine monophosphate vanish. rather, they ’ re trapped in the system. Since flatulence bubbles are compressible, then the brake pedal becomes spongy .
normally, the bracken system will function with a share of moisture in the organization. Over time, this moisture content increases and as a consequence, brake performance decreases. That ’ mho why “ besotted boiling item ” specifications are besides provided by the Department of Transportation. These “ besotted boiling points ” are outlined as follows :
DOT 3: 284 degrees F
DOT 4: 311 degrees F
DOT 5: 356 degrees F
DOT 5.1: 375 degrees F
As you can easily see, the wet boiling compass point of silicone brake fluent is importantly higher than it ’ south glycol-based counterparts. That ’ s because silicone fluid does not absorb moisture while glycol-based brake fluid does. When you take a look at a can of conventional glycol-based brake fluid, you ’ ll about constantly find a warn with respect to using the fluid immediately. The reason, of class, is moisture assimilation. Once the seal is broken, then moisture will attack the fluid in the can .
further to the decrease in brake efficiency when the fluid is intermixed with moisture, the body of water found in the system can attack a total of inner brake components. Things like disc brake pistons can corrode beyond animate, which in turn can create both a dangerous position and an expensive repair bill. On a alike note, it ’ south constantly a beneficial mind to use the same trade name of brake fluid in the system ( or the trade name you ’ re plan to use ) as a lubricant when assembling brake calipers and consort brake components .
so why wear ’ t the OEM manufacturers make the big switch to silicone-based bracken fluids ? Silicone brake fluids have some admirable qualities : They don ’ deoxythymidine monophosphate steep moisture and they don ’ thyroxine damage paint finishes if spilled. unfortunately they aren ’ thymine perfective. One problem is little compressibility under gamey temperatures. If the brake system is exposed to very eminent temperatures, the silicone fluid can compress slenderly with the conclusion leave being a spongy bicycle. In addition, silicone fluid is affected by atmospheric pressure. When a silicone bracken fluid-equipped vehicle is driven in gamey elevation conditions, the fluid can expand significantly — again contributing to a spongy pedal. far to this, many of the rubber components used in brake systems are manufactured from “ ethylene propylene rubber eraser ”. Some silicone fluids are not compatible with the “ EPR ” ( it causes the condom components to expand ) .
then what ’ s the answer ? Always use a brake fluent that is recommended by the brake manufacturer. Never mix brake fluid brands or types and make every effort possible to keep contaminants out of the bracken fluent ( adenine well as the brake system ). Once the protective seal is broken on a can of brake fluid, use it immediately. Never re-use brake fluid that has been bled from a system. It ’ s a disposable item. Silicone brake fluid can be used in cars that are driven very fiddling. last, to maintain the health of your system, try flushing out the previous diol fluid in your raceway car braking system on a even basis — replacing it with bracing DOT 3 or DOT 4 fluid. Your brake pedal will be much happier .
previous parts : function 1, Part 2, Part 3
Xem thêm: How to check and top up your brake fluid
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Source: Brake Dance – 4
Mark Williams Enterprises
765 South Pierce Avenue
Louisville, Colorado 80027
PH : 866-508-6394
Website : www.markwilliams.com
About the writer : Wayne Scraba is a racecar drug addict. His background includes operation of his own rush patronize, build up racecars ( some you might be familiar with, but we won ’ thyroxine suffer into it here ), building hot rod street machines ; he ’ randomness built custom motorcycles, restored muscle cars and played with off road bikes. Scraba has a assorted backdrop in writing besides : He ’ mho toiled as a magazine Editor, a technical Editor, a freelancer magazine subscriber and authored five automotive books. His byline ( good over 4,500 articles worth ) has appeared in well over sixty unlike high gear operation automotive, motorcycle and air travel magazines worldwide. Racecar addict ? Most probable !