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Bendix Police Brakes

Written by Police Fleet Manager Staff

The Bendix® POLICE Semi-Metallic Brake Pad was one of the new products introduced at PFE-Charlotte. Second only to tires, disc brake pads are the highest wear item in the police vehicle. In fact, many Preventative Maintenance programs call for a brake pad thickness inspection during every oil change. This also makes the best practice of rotating the tires at every oil change easy and obvious.

The problem with brake pads that wear quickly is the ill-advised temptation to replace the pads with whatever the local auto parts store happens to have. Big mistake. The rule has always been to replace the OE pads with OE pads, or OE-equivalent pads. And the burden of proof that the pads are truly OE-equivalent falls on the pad manufacturer. Many claims of OE-equivalence are made, but few companies offer proof beyond a reasonable doubt. Just because the brake pad fits on a police car doesn’t mean it belongs on a police car.

 

Just Use Whatever Fits

Not all pads that claim to be police-spec or OE-equivalent are actually so. For example, the NAPA website lists five different POLICE pads for the Dodge Charger. Three of these POLICE pads are ceramic. (Don’t use ceramic pads on police patrol vehicles!) One of these POLICE pads is non-asbestos organic, NAO. (Don’t use NAO pads on police patrol vehicles!) One of the pads is a semi-metallic. Semi-met is the right type, but the manufacturer is either unknown or open to change.

Finally, two of the ceramics are more expensive than the semi-met, while the NAO and one of the ceramic pads are less expensive. Of course, all are claimed to be OE-equivalent and identified as such. So, the lowest bid pad that fits and the second to lowest bid pad that fits, both identified with POLICE, are totally the wrong brake pad.

Just because a replacement pad is available in a size that “can” be used on your police vehicle doesn’t mean it “should” be used on your police vehicle. In fact, some pads should not be used on any police vehicle.

For example, ceramic pads should not be used on any vehicle likely to be in a pursuit. Ceramic pads run hotter than the correct semi-metallic pad, which raises the temperature of the entire brake system. And the hotter the ceramic pad gets, the worse it performs. The ceramic pad is clean, and it is quiet, but it does not do well during a pursuit.

Many auto parts store chains custom brand (rebadge) brake pads made by various, non-disclosed manufacturers. The problem is these sources may change without buyers knowing. One manufacturer may have the contract to supply the chain in 2013, entirely different from the supplier in 2012 and entirely different from the supplier for 2014. Brake pad compounds change often enough from the same supplier.

 

True and Proven OE-equivalent

Honeywell Friction Materials, makers of Bendix brakes is one brake pad company that is both 1) an OE brake pad supplier for some vehicles; and 2) has had their police pads independently tested against OE police pads. Their proof of OE-equivalence for the Bendix POLICE Semi-Metallic Disc Pads is Link Engineering’s Declaration of Conformity using Laboratory Brake Evaluation® in accordance with the OE baseline.

Bendix is an OE supplier to Mercedes, BMW, Audi, Toyota, Honda, Chrysler/FIAT, Mazda/Ford and Volkswagen. The Bendix POLICE brake pads are currently made in Canada. Another production facility in Mexico is scheduled to come online soon.

 

Born from Fleet MetLok

Bendix used their years of experience with the Fleet MetLok® pads to develop the Police pads. The Bendix POLICE friction materials used the Bendix Fleet MetLok as a starting point. Fleet MetLok has a long history of OE-equivalent performance in a wide variety of fleet vehicles.

Fleet MetLok is suitable for a wide variety of cars, trucks, SUVs, crossovers and both light and heavy trucks. The Bendix POLICE line is more focused on the police sedan segment. The Fleet MetLok remains the better choice for heavier vehicles, i.e., ¾-ton pickup or van and above. Where a Bendix POLICE parts listing exists, this is a better choice than the Fleet MetLok for police use.

Compared to the Fleet MetLok baseline, the Bendix POLICE friction materials excel in two areas: fade performance and pad life. The Bendix POLICE pads produce slightly shorter stopping distances. This new brake pad is also quieter. “We zeroed in on noise,” said Grif Jordan, North America product marketing manager for Honeywell Friction’s Bendix brand.

 

No Burnish Needed

The blue coating on the Bendix POLICE pads comes from their TitaniuMetallic™ II premier line of semi-met pads. The unique blue color of the titanium metallic coating is a sign that these pads do not need to be burnished after pad installation. The facts are that all other brake pads should be burnished (a series of increasingly harder stops from increasingly higher speeds) yet virtually no brake job includes this last step. With the titanium metallic coating, no burnishing is required. The Bendix Police pads stop with maximum force of the very first brake pedal use.

This is a first among major friction materials used on police vehicles. Nearly every automaker, nearly every brake pad supplier has a burnishing procedure for new brakes. The problem is that each brake pad company has a different burnishing procedure.

Worse yet, the burnishing procedure from the auto companies sometimes varies from year to year on the same make and model. Worst of all, virtually no one burnishes the brakes after a brake job…it is put the tire on and go back in service. The out gassing during the first few stops on an unburnished pad has indeed caused first or flash-flame on brand new brakes.

 

Independent Dyno Testing

Link Engineering tested the Bendix POLICE pads against the OE pads on the Dodge Charger Pursuit and the Chevrolet Tahoe PPV. They checked four areas important to police patrol: 1) maximum stopping power; 2) shortest stopping distance; 3) resistance to fade; and 4) quietest braking. “Equaled or exceeded” is an over-used term, but that is exactly how the Bendix Police pads performed in all four tests.

The maximum stopping power test conducted by Link Engineering is a variable-controlled dynamometer test. The program loaded into the dyno is that of a road course used by the police to test the overall acceleration, braking and cornering. Many police departments use the annual Michigan State Police tests and/or the Los Angeles County Sheriff tests as a purchase criteria. That is, passing these tests is part of the bid spec.

As a result, some auto, brake and tire companies have driven these courses with an instrumented car and then duplicated the exact courses on their dyno. It is easy to have the dyno accelerate to 60 mph, apply medium brake pressure, accelerate to 120 mph and apply max brake pressure, i.e., do whatever the test vehicle recorded on the road course for as long as it took to make four laps.

 

Shortest Stopping Distance

The shortest stopping distance is simply that: stopping from 60 mph with hot brakes. The shortest stopping distance test is conducted by Link Engineering immediately after the max stopping power test.

The fade test is a hot performance test that determines how long it takes for the brake pad to fade, i.e., how long before the stopping distances start to get significantly longer. The brake fade test is simple enough. Accelerate to 60 mph, and then apply the most braking rate possible short of ABS activation. Proven each year at the MSP and LASD vehicle tests, 12 stops in rapid order is not enough to fade police-spec, semi-metallic brake pads. While 12 stops from 60 mph, in this case, is not enough to cause brake fade, the 40 stop test protocol certainly is enough.

 

Quietest Braking

The quietest braking test is a sound test. The instruments record the noise made by the brakes in a wide variety of circumstances. A certain decibel threshold is established. Beyond this point, most drivers would find the noise objectionable or irritating. All brakes make noise as a semi-metallic surface is pushed against a metal surface. However, it is just the screech/squeal noise that is objectionable. So this test records how frequently during a specific dyno test the pads make those high decibel sounds.

The Bendix POLICE pads have a J-chamfer where the friction material meets the backplate. This relatively sharp angle means the contact surface remains constant as the pad wears. On pads with a more angled chamfer, the contact area gets longer as the pad wears. This causes both brake noise and an ever-changing contact area. Not so with the Bendix POLICE pads.

 

Pad Locked to Backplate

The Hot & Cold Shear Test is the ability of the friction material to remain attached to the backplate at all temperature extremes. The brake pad is heated to 500 deg F for 48 hours. This temperature and duration is enough to burn off all the adhesive between the friction material (pad compound) and the metal backplate. To pass this test, a mechanical bond must be used and the mechanical bond must be stronger than the strength of the friction materials. The pad compound must crumble before the pad separates from the backplate.

Many of the Bendix POLICE pads use a mechanical retention system to secure the friction material to the backplate. Something like the Velcro® hook and loop, the backplate has a wood rasp surface. These teeth engage the glued-on friction material, forming both a chemical bond (adhesive) and a mechanical bond (retention system).

 

More Development Tests

The dyno testing systems are used at different speeds and temperatures. Engineers then document any change in braking performance based on changes in temperature. The testing generally starts at 200 deg. F, which is relatively cool brakes, up to 400 deg. F, which is a normal operating temperature for most patrol vehicles.

High-speed testing is usually conducted at 90 percent of the speed limited top speed. For the police sedans that hit 150 mph, the testing involves hard braking from 135 mph. Cold testing starts with all of the brake components (rotor, pads, caliper) at 14 deg. F. The test involves emergency stops from 20 mph. The test then continues with the brakes at 32 deg. F, 50 deg. F and 68 deg. F.

 

Comparable Brake Wear

The one aspect of brakes that cannot be objectively tested is brake pad wear/pad life. Every fleet manager knows this varies from officer to officer, from precinct to precinct. In this regard, the Bendix POLICE pad is claimed to be “comparable” to OE pads in service life. Since the Bendix POLICE pads were OE-equivalent in other areas of brake performance, their claim of comparable wear is easy to believe.

The vast amount of brake pad development takes place on a dynamometer. This is a precision, controlled variable test stand that gives the best theoretical results. There is an interim step between the dynamometer and a limited production run on patrol vehicles. The on-board instruments record the pedal force, pedal travel and deceleration rate. However, police officers don’t drive dynamometers. At some point, the brake pad needs to leave the lab environment and hit the street. Bendix POLICE pads have been beta-site tested with the Westport, Conn. Police.

 

New Brake Pad Applications

The Bendix POLICE brakes were developed specifically for the police package and special-service package sedans, crossovers and SUVs. As new police vehicles are introduced, Bendix is developing new brake pads. For example, the Charger Pursuit got much larger brakes as a running change in the mid-2014 model year. Bendix will have pads for the 2014 ½ Charger in the fourth quarter timeframe.

Bendix POLICE brakes are available for the Ford CVPI, PI Sedan and PI Utility; the Dodge Charger and Durango; the Chevrolet Impala, Caprice and Tahoe. Bendix POLICE brakes will be available for the Chevy Silverado, RAM 1500, and Ford F-150 in the July-August timeframe.

As a rule, Bendix brake pads are professionally installed. From an availability viewpoint, that means the Bendix brand is less likely to be found in a local, after-market auto parts store like O’Reilly’s, NAPA, or Car Quest. Instead, Bendix parts are more likely to be available at specialty brake shops. The easiest way to find Bendix brakes is through the “distributor locator” on the Bendix/Honeywell website. Simply search by zip code.

“Equaled or exceeded” is an over-used term, but that is exactly how the Bendix POLICE pads performed both during dyno testing and on patrol. The Bendix POLICE pad can prove its claim of being OE-equivalent.


Published in Police Fleet Manager, Jul/Aug 2014

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