Brake friction servicing remains one of the most popular workshop tasks, but technology has not stood still – Rob Marshall looks at purchasing, fitting and up-selling advice.
MAKING YOUR SELECTION
Choice is not always the best thing. Aside from practical issues, including reliability of supply from the factor, selecting brake friction components has become almost bewildering, because the market has become saturated. Despite the many options available to garages, Borg & Beck has found that most workshops stick to just one brand. However, it reasons that the typical installer needs to understand the differences between the parts on offer (see our later advice on training) and relate them to the owner/driver, because of the differences in pedal- feel and longevity that may exist between different friction brands that possess different specifications, despite all of them being compliant with mandatory R90 standards. Research is, therefore, key. Delphi agrees and states that it uses over 130 friction ingredients to create 20 friction formulations to tailor braking performance for a particular vehicle application. This compares with some suppliers that, it claims, only offer two friction specifications. MEYLE advises that it can be a positive upsell move to offer customers a choice, instead of restricting them to a single brand, but you will need to be informed enough to advise accordingly.
Some factors have introduced their own brands, as a means of achieving economies-of-scale and building customer loyalty but, potentially, this courts confusion even further. Euro Car Parts (ECP) told us that it arranged to distribute the Pagid brand exclusively a decade ago, after it was acquired by TMD friction in 2002. Its reasoning was to combine the company’s widespread network and rapid delivery service with Pagid’s OE heritage. The strategy appears to have worked, with ECP reporting that the brand has grown phenomenally, although it is worth adding that the Pagid range extends beyond the friction components alone.
The final word, however, has to go to Delphi, which advises that, in order to avoid inferior quality products, choose a proven quality brand that has been engineered, manufactured and tested to OE standards.
BEYOND THE LEGAL MINIMUM
Introduced in 1999, the ECE R90 Regulation stipulated that aftermarket brake pads should perform within a 15% tolerance of certain OE test criteria. As of November 2016, the directive was extended to cover brake discs too. ECP highlights that, because braking is a lucrative market, everyone is looking to cash-in and increase revenue, resulting in the ‘OE Quality’ statement being used to indicate that a brand complies with R90 legislation. It warns, “Many customers have started to assume incorrectly that these brands supply components to vehicle manufacturers – that is not the case. A large percentage of the brands within the braking aftermarket do not manufacture components themselves, let alone supply vehicle manufacturers.”
Supplied to both vehicle manufacturers and the aftermarket, Federal-Mogul states that its Ferodo brand meets OE standards at the very least. It reveals that R90 legislation is a minimum standard for braking parts – for example, certain R90-compliant friction parts tend to have a standard type of noise control, or none at all, whereas Ferodo brake pads are designed with OE specific noise control features, such as chamfers and shims. Federal-Mogul reveals also that R90 conformity tests tend to take several hours, whereas OE testing can take six months and include more comprehensive testing that R90 might not consider, such as wet weather performance, temperature sensitivity, wear levels, fade, thermal conductivity, judder, durability and noise.
You might think, therefore, that only OE suppliers seek to surpass the basic R90 requirements for both discs and pads but this is not the case. The new generation MEYLE-PD range of brake friction components are also intended to perform at a far higher level than the basic ECE certification. Brake pad manufacturer, Comline, has introduced extra test procedures as well, such as hot sheer testing, wear analysis and noise tests, which it describes as R90-Plus.
Yet, we are not downplaying the role that R90 has in making it harder for sub-standard braking components to enter the UK car parc. All pads and discs that you fit must be supplied in a sealed box, each of which should bear a unique part number, official approval mark and evidence that permits traceability of the production process, such as a date, batch number, or source code. The box should contain fitting instructions in the correct language and the brake discs should be marked with a minimum thickness specification.
Buying extra parts, or a complete kit that includes accessories, can reduce labour times. Borg & Beck’s brake shoe kits, for example, are preassembled and it claims that you save up to 45 minutes of labour fitting time, compared to assembling and fitting the separate parts.
Dependent on the application, however, extra parts may be needed and it can be worth enquiring if they need to be ordered separately. Apec reports that braking hardware’s tensile strength reduced by 30-50% over a two-year period, so replacing shims, for example, is a wise idea, even though the old parts do not appear to have anything wrong with them. Meyle told us that 99% of its brake discs range is supplied with a new locating screw, because they tend to corrode to the hub and are unsuitable for reuse. Its MEYLE- PD brake pads kits include ancillary parts, in cases where the company views their replacement as desirable. While Delphi admits that its brake pads are supplied with calliper bolts, fixing screws and wear indicators, where deemed necessary by OE specifications, it supplies fitting kits separately in order to limit the number of part numbers in its range. Borg & Beck highlights that its brake fitting kits include all of the components necessary to complete the tasks, including clips, springs, pins and bolts.
While coated brake discs have been available for some time, unpainted brake discs are still widespread for older cars, so enquire with your supplier. While there is nothing wrong with unpainted discs (provided that the protective oil film is removed with brake cleaner prior to fitting), the rusting process looks particularly unattractive, if it can be seen through wide alloy wheel spokes – offering a coated alternative may be a useful up-sell for a cherished vehicle.
Comline told us that coated discs form most of the company’s range, which are salt-spray tested for up to 240 hours to ensure optimum corrosion resistance. This tough coating is resistant to petrol, oil, brake fluid and most wheel cleaners, as well. Borg & Beck says that its water-based zinc and aluminium flake coating on its BECKTEC Brake Discs not only increases the corrosion protection but also enhances the thermal exchange properties of the disc to optimise braking performance. A technician saves time, because coated discs can be fitted straight out of the box, with no cleaning/degreasing being necessary.
In light of increasing awareness of particulate pollution, affecting watercourses in particular, brake pad manufacturers have strived to eliminate heavy metals (especially copper) from their friction materials. Delphi and Meyle (the latter referencing its MEYLE-PD ‘next generation’ brake pads) told AT that working on reducing pollution and dust formation, while maintaining brake performance, is one of the many ongoing behind-the-scenes challenges that the brake friction industry faces.
The increased uptake rate of hybrids and EVs, however, has made drivers more aware of brake noise, because the natural sound of the friction materials working together is not masked by the noise of an internal combustion engine. Meyle reports that previously unnoticed sounds can be perceived as disturbing. Therefore, a complaint of excessive brake noise from an EV driver might be entirely normal but latest developments may provide an up-sell opportunity. Delphi advises that selecting a brand with NVH reducing technologies, such as its own, is increasingly important. As the typical driving style is modified to take full advantage of regenerative braking systems on hybrid cars and EVs, Delphi says that advanced corrosion on the braking system changes the wear properties of pads and discs and the aftermarket needs to be aware of the opportunities that this brings. Federal-Mogul adds that brake pads are more prone to glazing under light usage conditions, as well.
Perhaps the most obvious example of this is ZF’s TRW brand introducing the Electric Blue brake pads for EVs, as pictured. Designed to reduce braking noise, the pads are claimed to produce 45% fewer particulates than conventional pads. The current range covers 97% of the European EV car parc.
Noise grievances tend to be the commonest issues that damage customer confidence in garages, motor factors and brake component manufacturers. Unless the issue stems from grinding, caused by serious neglect that must be dealt with immediately, most other noises are more annoying than detrimental. Comline’s Dr Keith Ellis, Director of Braking Product Development revealed that:
“Squeal is caused by vibrations that result from the interaction between a brake disc, brake calliper and brake pad, which tends to be influenced directly by various internal and external factors, including the temperature of the disc, or pad, the ambient temperature in which they are operating, the speed that the vehicle is travelling at and the pressure being exerted under braking.”
Installing shims to the brake pad back-plate reduces this vibration and, therefore, controls unwanted brake noise. Comline states that there are multiple different shim derivatives available across the aftermarket, with differing levels of quality and performance, which vary between bonded gasket paper and complex laminations, using layers of different materials. For example, while Borg & Beck’s BECKTEC Brake Pads are not only grooved and chamfered to reduce noise, they also possess double rubber shims for anti-rattle and noise suppression qualities. Comline reports that its multi-layer Rubber-Metal- Rubber (RMR) shim construction is particularly effective at controlling unwanted vibrations, when combined with the pads’ noise-abating friction material and pad design. RMR is a standard feature on all new to range Comline brake pads and available on over 500 of the most popular references.
Therefore, the brake pad’s shape can influence brake noise, too, and is one reason why directional brake pads are becoming more popular. By varying the angle at which the friction material contacts the disc, both noise and vibration can be reduced. Correct installation is crucial. Directional pads being fitted the wrong way round is one of the most common installation errors that Federal-Mogul/Ferodo encounters, for example. This has prompted the company to upload a fitting video (http://bit.ly/2WvtsUC) to its website. Delphi adds that its directional pads use either a letter, indicating which side of the vehicle the pad should be fitted, or an arrow that indicates the rotational direction of the disc and, therefore, the direction in which the pad should be fitted. Consult the fitting instructions, should you identify the pads as being directional, by the presence of a chamfered friction surface, or a crescent cut out of the shim, where no arrow is provided. Incorrectly- installed pads, or not following the correct lubrication advice in the fitting instructions, can cause excessive noise, as might wear in either the disc, or calliper. An interesting method of curing squeal is provided by BG Products. Its Stop Squeal is applied to the pads’ friction material, which reduces the likelihood of the pad and disc sticking and reduces vibration.
It is claimed that braking performance is unaffected by the application. Judder, felt by a pulsing brake pedal under light braking, as well as vibration being detected and even heard, can result not only from a damaged disc but also by incorrect fitting. Apec highlights that not cleaning the hub sufficiently, and garages not performing a run-out check, are two of the most common fitting errors that it encounters. Fitting good quality parts and providing the customer with point-of-sale advice about driving techniques for bedding-in brakes will also help reduce the chance of a dissatisfied customer returning for warranty work.
Federal-Mogul warns about misdiagnosing the brake pad as the source, when noise could emanate from many other parts, from the wheel bearing to the ball joint. This is more of an issue on newer vehicles, where increased non-braking components are produced from aluminium, which tends to resonate more than steel.
Federal Mogul advises that it encounters many garages installing new pads but not replacing worn discs. This tends to result in mushy brake pedal feel, increases the risk of noise and hot spots developing on the pad. Yet, when installing new pads and discs together, avoid mix-and-matching parts, because the friction surfaces are designed to work best together for optimum performance, longevity and anti-noise/vibration characteristics. Delphi Technologies, for example, offers an extended warranty only when its pads and discs are installed together.
For information on APEC’s IMI approved Light Vehicle Manual & Hydraulic Braking Systems, contact its Techmate Team on 01174 288090. Federal Mogul, meanwhile, offers Garage Gurus, a dedicated resource that provides training and technical support. Its ‘Gurus Online’ provides a 24/7 online training portal that encompasses over 30 courses, all of which are completely free of charge. ‘Gurus On-Call’, sees technical specialists provide fast answers for product and diagnostic questions either via telephone or Skype. You can also check-out over 40 on-line tutorial videos on the Garage Guru’s YouTube channel.
For 2019, Delphi continues to develop its range for newer models especially, to provide garages with an opportunity to repair newer vehicles sooner. It highlights that new components will be supported by its usual comprehensive training and technical support. Comline has extended its range of coated brake discs to cover the Ford Fiesta (2017-onwards), Jaguar F-Pace, XE and post 2015 XF models, the Honda HR-V (from 2015), the current production Hyundai Tucson and the Kia Sportage.
Meanwhile, Borg & Beck is emphasising its new point-of-sale materials, pictured. Aside from its ‘Brake Disc Installation Best Practice’ poster for the workshop for easy reference, it has added a rear-view mirror hanger in its brake disc boxes to help educate the driver to observe the critical bedding-in processes, such as avoiding heavy braking during the first 400 miles. It also advises that technicians pass on hints about poor driving practice, such as sitting stationary, often after heavy brake applications, with the footbrake applied firmly, which creates hot spots and increases the risk of judder developing. This can be an issue particularly with both automatic transmission vehicles and those featuring ‘Stop:Start’ technology.