A visit to Federal-Mogul’s production site reveals surprising truth behind brake tests…
Necessity is the mother of all invention and way back in 1897, the beginnings of the modern brake pad could be found on Dr Herbert Frood’s workbench within his humble shed, which still stands in the grounds of Federal Mogul’s production facilities in Chapel-en-le-Frith. The father of the Ferodo brand developed and patented a rudimentary, yet effective, braking system using wood, rope and leather to solve the problem of brake failure on carts hauling stone out of the Peak District quarries down to the canal network. The next twenty years saw the product evolve until during the 1920s, the first brake lining using asbestos was introduced. The damaging effects of this naturally occurring fibrous material were not realised until many years later but by 1980, Ferodo was producing pads with zero heavy metals and no asbestos and they were the first company to introduce copper-free brake pads in 2014. Alarm bells first rang on the effects of copper on the environment in San Francisco bay – it was discovered that brake dust entering the storm drains resulted in many dead fish! Legislation will mean that all pads will be copper-free by 2025.
THE ART OF TRIBOLOGY
As expected, there is a highly-controlled science behind making braking material and increasing restrictions are in place to reduce dust and emissions. During our visit to Federal-Mogul, R&D manager David Holme explained that modern brake pads are highly sophisticated and are probably the most complex materials fitted to a vehicle. The company is at the forefront of using ‘tribological fingerprinting’ to understand and predict chemical interactions and this work led directly to the
Eco-Friction copper-free range.
Pads can contain thirty individual ingredients, from a stock cupboard of several hundred materials, each with different physical characteristics and uses, and it is up to their material scientists to combine the ingredients in a balanced way, to produce the best compromise of longevity, price and performance – depending on the customer’s preference.
Surprisingly, it is only two per cent of the brake pad which is abrasive and actually stops the vehicle, with the remaining ninety-eight per cent made up of binders, strengthening agents and lubricants, which are added to enable it to do its job under all conditions. In particular, getting the lubricant mix right is crucial to delivering the same performance and feel each time – and this is what you are paying for with OE pads.
THE GREAT BRITISH BAKE OFF!
The material scientists within the R&D facility, a miniature version of the factory next door, compare the process of making a brake pad to that of baking a cake. First, hundreds of both dry and
wet ingredients are weighed for the experimental prototypes and then mixed using different techniques, depending on the ingredients. Steel fibres are then added in what looks like an industrial cake mixer and then either ‘cold pressed’ or ‘hot pressed’ into pads. Backing plate features are then added to address safety and noise issues before curing, then it’s time to grind and add finishing touches, such as scorching the plate to reduce bedding time and adding features such as grooves. The pads finally head to the spray booth. The prototypes are then ready for the test labs where the chemical and physical properties are analysed in 20 various tests, including: compression, shear and stiffness tests, and 24 and 48 hour cycles in the salt spray tank to test corrosion behaviour.
High temperature thermal tests are also performed to see what temperature the pad burns out to check brake fade. Furthermore, sonic equipment checks the natural frequency of the pad and chemists look under the microscope to check for any defects in the mix. Light vehicle dynos are used to simulate any driving conditions and prove more consistent over real life testing – the aim
is have a product which gives the same pedal behaviour under any temperature or driving condition. The biggest challenge faced by VMs is judder and squeal, so thorough NVH testing is carried
out to isolate all sounds – although issues tend to stem from suspension and caliper design and not the brake pad material itself. Damping material can be added to the brake pad to prevent the sound being generated at source.
The final stage is vehicle testing – loaded vehicles fitted with pressure and temperature regulators are put through their paces at test tracks around the world, including MIRA in the UK. If any issues arise at any stage, the mix or manufacturing technique is altered, with hundreds of parameters to consider and balance, and the process starts all over again. It usually takes around 18 months to develop a prototype into a new product ready for market. Once formulations are approved, the pads go into production within the onsite factory, which currently produces in excess of 24 million pads each year for vehicles such as the VW Golf and Ford Focus. Largely, production is for OE – although everything that goes into the OE box also goes into the aftermarket Premier range box, with the aftermarket bound products made on exactly the same lines, only the car maker’s mark and sticker on the box differentiates them.
The Ferodo brand has certainly stood the test of time – 120 years on from Dr Frood’s first brake pad within a humble shed, which proudly stands by the entrance of Federal Mogul’s Technical Centre.
Braking technology continues to evolve through necessity; to reduce emissions, be kinder on the environment and deliver on performance and Federal-Mogul’s commitment to innovation and quality
will ensure their place in the market for many years to come.
Take a look at Ferodo’s online technical support at www.ferodo.co.uk to find solutions for common technical problems, like judder, noise and vibration, in-depth guides on visual problems on brake pads and discs and step-by-step installation guides on difficult brake installations.
R90 – THE EU BRAKE TEST THAT STOPS SHORT OF EVALUATING COMPLETE BRAKING PERFORMANCE
All vehicles manufactured after 1998 must have brake pads that comply to ECE R90, a performance test which seeks to guarantee equivalent performance within 15% of the original part. Around 400 of these tests are conducted by Federal-Mogul every year, each witnessed by a government official to earn the approval. The legislation was introduced back in 1990 with the aim of eliminating unsafe product from the market, but the test is very specific – testing vehicle stopping only under dry conditions, at 80% of the maximum speed of the vehicle and at gross vehicle weight. Federal-Mogul believes a wider range of testing is really required to reflect the variety experienced in real driving conditions.
For example, R90 legislation makes no assessment under wet driving conditions – surely an essential measure of safety? Using a recognised OE test to measure average stopping distances in wet conditions, quality competitor products stopped a car at 60 metres in the dry but in the wet,
only managed 250 metres, with one taking over 600 metres to stop the vehicle – and this would still pass the R90 stamp of approval! All Ferodo product is tested under both wet and dry stopping conditions to ensure satisfactory performance every time.
– Of the 10 top-selling vehicles in Europe, Ferodo was fitted as OE to 8 of them.
– Ferodo Premier range has been shown in tests to provide the shortest stopping distance, guaranteed 10% to 68% longer pad life, OE matched noise control, best pedal feel, while still being
kinder to the environment
– By 2025, all brake pads will need to be copper-free. Ferodo launched its pioneering Eco-Friction pads back in 2014, providing the same stopping power as Ferodo Premier brake pads. The launch of the Eco-Friction zero copper pads on the new Mercedes-Benz C-Class marked the first time ever
that such an innovative technology was made simultaneously available to the OE market and the