Brake Discs to Replace or Not to Replace?

Why would you be told to replace discs as well as pads? While there are some who would say it is only for the garage to make more money here are 7 other reasons that you may be told or advised to replace them!

Any reduction in braking efficiency will result in increased braking distances whatever the weather

1) Vented disc vents corrode

2 things can happen one the joints between the 2 discs corrode & get thin then separate OR the corrosion can build up and block the vents so the brake over heats. The photo shows excessively corroded disc on left with blocked vents. New disc on right showing clean cooling vents wear limit at top.


2) Discs can wear unevenly

New pads & unevenly worn discs will give a reduction in braking efficiency as soon as they're fitted.

3) Distorted discs

Distorted discs will cause a vibration when braking maybe uneven tyre wear in severe cases may even make the car vibrate when braking.

4) Brake pads not replaced before minimum limit

If the brake pads are allowed to wear past the minimum then instead of having a friction pad rubbing the disc to slow it down it will be metal causing a grinding noise and unevenly worn discs, over heated discs & potentially making the vehicle pull to one side when braking. The photo shows new pad on left & pad worn past limit to metal on right.


5) Surface corrosion

When the braking surface gets corroded not all of the designed surface works so reduces the efficiency of your brakes. The photo shows corroded braking surface on left disc vs new disc on right.


6) Over heated discs

Over heated discs will look red & the braking surface may have the quality & strength reduced by the excess heat causing premature corrosion.

7) Excess wear

Thinner discs will over heat & lose braking efficiency.