Information that is vital to the maintenance of

The Brake System

The brake system on a car or truck works by converting kinetic energy into heat energy. The friction between the brake pads and rotor creates heat, but when brakes get too hot bad things can happen. The most dangerous thing about hot brakes is the decrease in braking power known as brake fade. However, heat is a normal product of the braking system. The problem is, too much heat, for every increase of 100 degrees over the normal operating temperature, brake wear doubles. The longer brakes stay at high temperatures, the more wear they experience. Also, at high braking temperatures, a gas is expelled by the brake pads, (known as "out-gassing"), which forms a barrier between the pad and rotor. The out-gassing effectively pushes the pad away from the rotor reducing brake efficiency.Information that is vital to the maintenance of brake systems.

Know Your Boiling Point

The average driver uses his or her brakes approximately 75,000 times a year and expects them to function properly each and every time. With police vehicle operation, the number of brake applications can more than double that amount.(1) Within the braking system of all automobiles exists brake fluid, a highly critical component essential to brake operation. Brake fluid serves to produce the braking action as well as to protect and to lubricate brake system components. Every driver depends on brake fluid for stopping capability(2). The use of a high quality brake fluid is essential to assure the safety of the driver and passengers traveling in the automobile. As a public organization, we owe to the motoring public and our employees the safest environment possible.

How Do Brakes Work?An automotive hydraulic braking system consists of a master cylinder, four wheel cylinders, metal tubing and flexible rubber hoses. This hydraulic system attaches to frictional components that are comprised of brake shoes and drums or brake pads and discs. The brake fluid is contained within the system assembly. When pressure is applied to the service foot brake, the master cylinder exerts a force of fluid. This force actuates the wheel cylinders to push the brake shoes against the brake drums or the pads against the discs, resulting in the braking action. Application of the brakes turns the energy of the vehicle into friction heat at the brakes.(3) This brings the brake temperatures to high levels. If the brake fluid has been contaminated by excessive usage of high heat the boiling point can greatly be reduced in a short period of time. A vehicle that has been in service for 18 months with 25,000 miles of service, could have the working temperature of the brake fluid reduced by as much as 25%. If the fluid's working temperature were reduced by 25%, the moisture content would be equivalent to 3%.(4)

Brake fluids classified as DOT3 and DOT4 are naturally hygroscopic: that is, they possess a strong tendency to absorb water. Air can contain varying amounts of moisture depending upon the relative humidity. This moisture can find its way into the brake system through flexible hoses, thus contaminating the fluid. Moisture contamination directly results in reduction in the brake fluid boiling point.

The frictional components in a braking system generate very significant amounts of heat, especially vehicles being operated in severe conditions like a police vehicle or service vehicle in mountainous regions. Vehicles used in operations such as these could have an increase of brake fluid temperatures of as much as 20%. This combination of higher heat and a reduced boiling point increase the possibility of fluid vaporization or vapor lock. Unlike brake fluid, vapors are highly compressible. When brake fluid becomes more compressible it loses its ability to transmit the necessary force to effectively stop an automobile. In the loss of brake force comes the loss of pedal response and conceivably, even loss of braking action. Vehicles equipped with Anti-lock Brake Systems (ABS) are much less likely to skid out of control, especially when the roadway is wet or slippery. The anti-lock system pumps the brakes automatically up to 15 times per second, thereby avoiding brake lock-up and skidding. The results are maximum braking and increased control. ABS systems, in some vehicles, send a sense of reduced resistance to the brake pedal. General Motors, in their Chevrolet Caprices, have added a booster kit to the vacuum booster, which increases the amount of resistance felt in the brake pedal. GM has also added larger wheel cylinders to the rear of the vehicle to create more braking power. (5) This also creates more heat in the brake components.

Conventional DOT3 brake fluids will absorb and average of 2% or more of water in the first year of usage. In that period, the boiling point can drop from 401 degrees to 250 degrees, a reduction of over 150 Fahrenheit degrees.(6) Brake fluid designated a DOT4 possesses an important characteristic, having low moisture activity or improved ability to resist boiling point drop. This boiling point drop becomes essential in assuring safe brake operation. The following reflects both the minimum wet boiling point requirements for DOT3 and DOT4 brake fluid. (Wet boiling point refers to the resulting boiling point after moisture accumulation has taken place under controlled standards.) Taken from SAE.Minimum wetboiling pointDOT3

284FDOT4

311F(7)

Summary

A number of automobile design changes have occurred in recent years which directly or indirectly affect the braking system. The major influence on design changes has been for fuel economy. Drastically modifying the vehicle aerodynamics and design reduces turbulent air flow under the vehicle to lower the wind drag factor. Unfortunately this also results in a reduction in cooling air past the brake discs and drums. This potentially translates to significantly higher brake fluid temperatures in the wheel area. Improved aerodynamics and engine turbo charging have served to increase under hood temperatures. This will increase the temperatures in all brake components, from master cylinder to the rotors and drums. Front wheel drive vehicles and smaller lower profile tires equally increase brake fluid temperatures. (8)

The boiling point of new DOT 3 brake fluid is 401 degrees Fahrenheit. Contaminates such as moisture, dirt and corrosion greatly reduce the boiling point of brake fluid. High temperatures encountered in ABS disc brake applications require hydraulic fluid specifically formulated to withstand the higher temperatures than normally experienced in drum type brakes. Modern hydraulic brake fluids are designed for high boiling points because of the extended temperature ranges prevalent in disc brake service. Small amounts of contamination such as foreign material, vapor and water greatly decrease the boiling point. When the service temperature exceeds the reduced boiling point, contaminated brake fluid will vaporize and prevent positive braking on the subsequent application. Besides materially reducing the boiling point, moisture promotes rust in steel brake lines, sludge in cylinders and corrosion inside wheel cylinders and calipers.

References

Ford Motor CompanyGeneral Motors Corporation (8)Friction Advisory ServiceNAPA UnitedSAE (6)Brake Design and Safety Bosch Automotive Handbook Motor Trend MagazineNAFTA Fleet Bulletins OTC Tools & TechniquesEIS Brake Parts (3)Brake Tech/Talk volume (4)Castrol North America (John Demko) (1,2,5,7)Wagner Brake ProductsWSP Fleet BulletinRevised Code of WashingtonCode of Federated RegulationsColumbus Dispatch newspaper (4)

Brake Fluid Comparison Chart

BrandWet Boiling PointDry Boiling Point

Castrol SRF518F590F

Motul RBF600420F593F

AP-600410F572F

ATE-Super Blue392F536F

Valvoline333F513F

Castrol LMA311F446F

Ford HD290F550F

Wilwood 570284F570F

PFC-Z rated284F550F

AP-550284F550F

A word about brake fluid.DRM recommends Castrol SRF or Motul RBF600 due to their high wet boiling points. All brake fluids absorb moisture, some faster than others (except silicone which is not recommended for anti-lock brake systems). Castrol SRF resists moisture contamination (non-hygroscopic) more than any other fluid we tested, therefore change intervals can be greatly extended. This reduces the effective cost over a season of racing. Many drivers say that they can run the same fluid all year long with only bleeding off the fluid in the calipers for each event. This way a can or two will last all year. Other fluids (hygroscopic type) require additional flushing of the system for each track event to maintain the lowest percentage of moisture and the highest boiling point. For cars over 3000 pounds on high speed road courses DRM recommends brake fluids that do not fall below 400F wet boiling point. Source: http://www.dougrippie.com/Stainless Steel Brake Lines The primary purpose of stainless steel braided brake lines is to improve the brake pedal feel, i.e. to make the brake pedal firmer. Stainless steel brake lines are typically constructed of a PTFE (teflon) core - through which the brake fluid travels, which is covered with a nylon or kevlar braided sheath, over which stainless steel fibers are braided on the exterior. Some stainless steel brake lines also have a silicone cover applied over the stainless steel braiding, to prevent dust and debris from working into the space between the PTFE core and the stainless steel braiding, which can wear down the PTFE core, and thus result in brake line failure.For a street driven vehicle, we recommend NOT installing stainless steel brake lines, as they require more "maintenance" than OEM rubber brake lines. By maintenance, we mean regular inspection for leaks or wear. The stainless steel braiding provides protection against road debris which could otherwise cut or rupture an OEM rubber brake line, but unless you are willing to inspect your brake lines every 3 months or so, installing stainless steel brake lines would present more of a liability than any realistic performance benefit.For a track driven vehicle which has its brake system inspected regularly, and where the driver wants the most consistent and firm brake pedal feel possible, then stainless steel brake lines can be installed with excellent results.For more than 20 years, Goodridge has been supplying hose and fittings to the world's leading race teams. Ongoing research and development means that the lessons learned on the track are passed on to you, the serious user. Goodridge Stainless Steel Brake Line Kits feature the finest quality hose, consisting of a PTFE inner with a stainless steel outer braid. This eliminates the spongy pedal feel under arduous conditions, giving greater braking efficiency and providing superior resistance to abrasion and corrosion. They also improve the good looks your Grand Am already has. They're perfect for street or track use, are 50-state DOT legal and are also guaranteed forever against manufacturing defects!

NOTE: You must re-use your factory bolts as the ones that are included in the kit are too short and can cause damage to your caliper. We are working on a solution but it is perfectly safe to use your old bolts. Source: http://www.pfyc.comAnother great manufacture of SS brake lines by Earls Performance Plumbing. Earls S Brake Lines are the choice of most Corvette Racers Earl's Hyperfirm Stainless Steel Brake line kit.

Race cars have used flexible brake hoses of extruded Teflon for decades.

Protected against abrasion and swelling by a sheath of tightly braided stainless steel wire.

Resistance to "line swell" improves both the firmness or "feel" of the brake pedal and reduces braking reaction time. Source: http://www.lgmotorsports.com/index.htmBrake Pads

Which brake pad compound should I get?

The type of brake pad compound you use on your vehicle depends on the type of driving you plan to do; e.g. street, auto-cross, road course (track), Solo I or II, racing - sprint or endurance, etc. Brake compound selection is also dependant on the type of vehicle you own and the type of brake system (e.g. disc or drum) your vehicle has.Keep in mind that if you are using your vehicle for more than one or two types of driving, then compound selection becomes more "touchy", as you are asking the compound to perform well under widely varying conditions. A pad compound that performs very well on the track, by providing a strong initial bite and a high temperature range, for example, may not work well on the same car when used in an auto-cross event, as the front brakes may lock-up after they are heated up, etc.OEM ceramic pads from GMPartsDirect.com you WILL get AC Delco pads in an AC Delco box. http://www.gmpartsdirect.com/results.cfm?singlepart=1&partnumber=88909667High Performance Carbon Kevlar Street Pads

An excellent choice for replacing stock pads. Their versatile material works well on vehicles used for street and light duty racing. These pads reduced thermal transfer to the caliper by means of a ceramic insulating barrier between the pad material and the backing plate.Hawk Performance HP PLUS compoundIt can take the heat at the Track and get you home safely without having to change your brake pads in and out. This compound was designed for the serious street and autocross enthusiast. Extremely high friction output, Race worthy for autocross, Race worthy for club racing events, Elevated temperature resistance.

PFC Z-Rated Pads The pad of choice for the street racer, auto-crosser and drag racer. The Z-rated material delivers more brake torque with less pedal effort than stock brake pads.PFC 01 Compound ( Racing only not for street use ) The 01 race pad is a newly developed compound. This pad is the flagship pad for touring cars and most saloon car applications. In terms of supreme braking, it supercedes all of Performance Frictions earlier Compounds. It takes more heat to get this pad to function as intended but at the same time it has an extremely high heat tolerance, being able to see temperatures in excess of 1200 degrees Fahrenheit without seeing excess wear. The ideal working temperature for this pad is between 600 and 900 degrees Fahrenheit. While being a more difficult pad to modulate, its release characteristics are this pads strong suit. PFC 01 is an extremely high friction compound, with a high flat torque curve, providing excellent modulation. Better pad wear than the 83 compound, with a smooth, fast release. PFC 01 polishes the rotor without pad material build-up. This compound has had success in CART, Winston Cup, Busch, ASA and Featherlite Modified Series racing.

Carbotech Panther Plus and XP Brake Pads http://carbotecheng.com/main.htmA high torque brake compound delivering reliable and consistent performance over a very wide operating temperature range (150F to 1300F). Advanced compound matrix provides an excellent initial bite, high coefficient of friction (0.54-0.56), and very progressive brake modulation and release characteristics. Extremely high fade resistance, very rotor friendly, and excellent cold stopping power. Primarily designed for track use, but can also be used with good results on the street.How do I properly bed-in my new brake pads?

In order to achieve maximum brake pad life and performance, it is necessary to properly "bed-in" your new brake pads. In general, the more aggressive a pad compound is (i.e. higher coefficient of friction and compound material density), the more aggressive the bedding in process needs to be.For Carbotech Engineering's Super Street-F (7266), Panther (1104), and Panther Plus (1106) compounds, you should use the following bedding in process:

(1) Brake from 50mph down to 10mph using moderate pedal pressure. Repeat this process 6 to 8 times in succession.

(2) Cool down the brakes by driving for 10-15 minutes on the highway. Avoid having to use the brakes during this cool-down period.

(3) Repeat step (1), but use very heavy pedal pressure. Brakes may fade during this set of braking, so please use caution.

(4) Repeat step (2).

(5) Park the car for 4 to 6 hours after the brakes are cooled down. Allowing the pads to "rest" overnight is preferred.

Cars with a curb weight of over 3000lb. may require one "light" track session to sufficiently heat up the pads, followed by a good cool down period, in order to ensure both pad longevity and maximum potential brake torque.

Rotors

Cross-drilling used to be the gospel to racers back in the 70's but those racers had the budget and the know how to change drilled rotors after every time out on the track to avoid stress crack risks. This just isn't practical for commercial or normal street use.

One of the biggest misconceptions with drilled rotors is the Porsche OE rotor. If Porsche can have a drilled rotor why can't I? Actually factory Porsche rotors are not drilled at all, they have their holes cast into the structure of the rotor at the casting stage. The holes then become part of the molecular structure and not an after thought when the rotor is finished. Slotting is the process of milling tracks in the face of the rotor but not breaking through the iron and weakening its molecular makeup.

Power Slot tapered slot design has clearly replaced crack prone cross drilled rotors as the performance rotor upgrade of choice among automotive enthusiasts.

Slotted OnlySlotted only rotors in any extreme service application. These would include racing, autocross, larger trucks and SUV's, and vehicles that exhibit chronic brake problems.

The nature of the slotted only rotor gives the greatest amount of braking surface,helps keep the pads clean, and increases initial brake 'bite'.

Note: Due to the nature of slotted rotors- a slight hum may be evident under heavy braking.

New Stock Replacement Slotted Brake Rotors

Slotted rotors are Nickel Plated for a durable, corrosive free finish.

Slotted rotors vent the gases from the pads for improved stopping power and reduced brake fade.

The thicker design is resistant to warping unlike the factory rotors.

Works best with Carbon Metallic Pads.

Do I need to resurface (i.e. turn) my rotors when installing new brake pads?

In order to ensure a uniform mating surface between the new brake pad and existing rotor, it is optimal to resurface the rotor prior to installing and bedding- in new brake pads. Resurfacing the rotor will also help ensure maximum pad life and braking torque (i.e. stopping power). Further, when changing from one brake compound to another, especially when switching from a "carbon-metallic", "carbon-kevlar", or "ferro-carbon" brake pad to a ceramic-based brake compound, such as Carbotech Engineering's line of proprietary compounds (namely Panther Plus and Panther), it is necessary to turn your rotors to remove any existing friction material deposits on the rotor. These friction material deposits (called "film transfer") can often interfere with the proper "bedding" of new brake pads and, additionally, can cause a notable shudder during the initial stages of new pad use.Keep in mind, however, that when resurfacing the rotor, to make sure you are within 20% of the factory specified rotor thickness after resurfacing, or else your rotor will be more prone to warping and cracking, or otherwise present a condition where catastrophic failure may occur (e.g. a rotor may crack severely and then shatter under hard braking).

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