Modern Brake Fitment and Bedding-In Guide
The automotive industry is fast-changing in all areas – especially brakes!
Aftermarket replacement parts are regulated by quality assurance standards such as ECE R90 (European Standard) or ISO9001 (International Standard). The demand for these aftermarket OE quality replacement parts is ever-increasing, which is a great thing!
This increasing demand has led manufacturers to explore new methods of producing and finishing products, leading to the emergence of new technologies in aftermarket brake replacement.
Brake rotors from many leading brands are now being coated in anti-corrosion material, which has some benefits:
- Fast fit – no pre-cleaning required
- No oxidation in the fins – providing better heat dissipation while braking
However, these coatings also have drawbacks when rotors are not installed and bedded-in correctly.
We are finding that a number of customers have the same complaints when replacing disc rotors and pads, these are:
- Pads seem to be taking longer to bed-in or are “not working properly”
- Squealing or excess noise when braking
- Brake shudder
The days of fitting rotors, cleaning off the anti-rust coating, installing brake pads, then then hitting the road to bed-in the brakes via 4-6 medium-hard brake applications – you know, the old “get a bit of heat into ‘em” method – are LONG GONE!
The new coatings on rotors – now seen in a large number of brands – along with new technologies in friction material (pads) and metallurgy (rotors), means it is time to use different techniques when installing and bedding-in brakes.
The New Way
- DO NOT apply brake cleaner or the like to any coated rotor – These chemicals will break down the coating, forming lumps on the pad contact face, leading to DTV (shudder)!
- Clean and lubricate caliper sliders, also lubricate the back and end of the brake pad with an approved, high-temp brake caliper grease (sparingly, wherever it contacts the caliper and bracket). This allows the pad and caliper to move and slide freely, helping eliminate vibration and therefore eliminating noise.
- Bedding-in brakes is all about getting the pad material to “talk” to the disc rotor material. Under a microscope, brake pads that are bedded in correctly deposit a transfer layer of material into the disc and vice versa. When bedding-in on the road it is imperative not to get the brakes too hot too quickly! Think “clean” – The bed-in coatings on pads are there to help clean the coating off the rotor face. If you get the brakes too hot too straight away, you can “cook” the coating into the rotor and pad face, “glazing” the rotors. This also means that the pads and rotors aren’t “talking” – leading to poor pedal feel (with the pads not working correctly) and noise.
Today’s Bed-in Procedure
So, with all of this in mind, the ideal bed-in procedure to follow is:
- 4-6 very light brake applications, don’t stop the vehicle completely (60kph – 40kph), think “clean” – NOT HEAT! Then progress to 4-6 light brake applications (60kph – 20kph), allowing at least 300m between applications.
- After this, drive the vehicle for a few kilometres under normal traffic conditions, using the brakes appropriately. Then, the finisher – 4 medium braking applications (80kph – 40kph), also allowing 300m between braking stops.
- Finish your test drive under normal conditions. Advise your customer that it will take up to 500km of normal driving conditions to fully bed-in their brakes, cautioning them to not get the brakes unnecessarily hot during this time.