Brake discs should be replaced when the thickness of the disc reaches the minimum allowed thickness. This measurement is clearly etched on the disc rotor outer periphery.
Worn brake discs will affect the braking efficiency of your vehicle. Signs that your brake discs are worn are: Brake shudder, discs cracking and sometimes disintegrating. All of this can cause extensive damage to the brake pads, brake discs and the rest of the vehicle braking system.
Both brake discs on the same axle should be replaced at the same time. This will extend the life of your braking system, and will allow all of the safety critical components to operate in equilibrium.
Loosen the wheel securing nuts. Jack the vehicle up and remove the relevant wheel. Use a 2-ton trestle as a safety support beneath the vehicle. Remove the wheels from the vehicle. Ensure that the handbrake is fully engaged to ensure that the vehicle remains stationary. This will prevent it from moving around on the trestle.
Open the vehicle bonnet and remove the brake fluid reservoir cap. Wrap a thick absorbent cloth around the filler neck to absorb any brake fluid which might overflow.
Loosen the bleeding screw slightly before pushing back the brake piston. This will avoid contaminated brake fluid from returning into the calliper, as this can potentially damage the internal rubber components and seals. The brake piston must be forced back into the calliper, this will release the brake pads from the discs. A special brake pad retraction tool will make this task easier to accomplish.
Nip the bleeding screw to avoid air from entering the brake fluid system. Carefully examine all the seals and rubbers for visible damage and/or leaks.
Remove the two securing bolts which hold the calliper mounting or housing to the strut / cradle. Remove the calliper and then the brake disc securing screw. Remove the brake disk, and check for visible rust and road dirt. Remove any dirt or rust on the brake disc. It is essential that all dirt, rust and debris be cleaned at this stage. Fit the new brake discs.
Re-fit all of the above components in reverse order of removal, ensuring that all of the relevant components are cleaned before installation. Double check that all securing bolts are correctly tightened.
Re-fit the wheel. Pump the brake pedal a few times to enable the new brake pads to make contact with the brake disc via the piston. Replace the brake disc on the opposite side of the axle by repeating the above procedure. Remove the trestle and lower the vehicle.
Remove the cloth from the brake reservoir and check the brake fluid level. Top up the brake fluid level if necessary, and replace the brake reservoir cap.
USEFUL TIP 1:
Apply the brakes gently for the first few kilometres after replacing the brake discs. This will allow the brake pads to bed properly against the brake disc mating surface area.
USEFUL TIP 2:
Inspect your vehicle’s brake components at least once every two months.
USEFUL TIP 3:
Replace your vehicle’s brake fluid once every 12 to 24 months.