Brake Vibration (judder)

ProCut on car brake lathe
Brake Discs being aligned with on car brake lathe to overcome brake vibrations

Most motorists at some point will experience brake-judder / vibration under braking this may be light braking or hard braking and will be felt as shaking of the steering wheel and even pulsing of the brake pedal.

The Garage says my discs are warped

This is probably the most common statement we hear from consumers, who report that the garage has told them their discs are warped, in fact we have heard some really amusing comments such as;

  • The brake discs are made of chocolate
  • They have warped because they were cheap
  • They have warped because they are poor quality

I personally have seen a huge amount of brake discs in the 25 years I have been in this industry, and I can say hand on heart I have never seen a chocolate brake disc fitted to a vehicle, in fact the mechanics I know would most probably eat the chocolate brake discs before you could collect your car.

The most common causes for brake vibration is disc thickness variation which is known as DTV, this is where the brake discs have worn unevenly causing high and low spots on the discs, whilst it is possible to have a badly manufactured brake disc the cause of DTV after use will normally be a cause of poor fitting techniques by the person fitting your brake discs, this could be the mechanic has not noticed a problem with the caliper pistons or slides or something as simple as not preparing the hub service before mounting the new brake discs. The ensure the new discs are running true to the hub the mechanic should carryout a Dial Gauge Test where the mechanic can actually measure the runout to ensure this is within the vehicle manufacturers specification, if it is not the mechanic should then measure the hub runout without the disc mounted to determine in the runout is a cause of the disc or the hub. If the correct measurement cannot be obtained the discs should not be fitted until the cause has been ascertained as fitting will lead to DTV.

Should you be unfortunate enough to suffer from brake vibrations after a few months / 2-3 thousand miles it is possible to resolve the issue by first rectifying the original cause of DTV and then by aligning the discs to your cars hubs using specialist equipment known as a on car brake lathe.

Poor quality brake discs are really a thing of the past, because modern vehicles require brake discs that are manufactured to high standards, aftermarket manufacturers have had no choice but to invest heavily in their production plants.

Vehicles that were manufactured after 1st November 2016 have to be fitted with ECE R90 certified brake discs, ECE R90 brake discs are your assurance that the brake discs you are purchasing are manufactured to the same high standards as the original equipment brake discs. Aftermarket manufacturers are now producing brake discs for vehicles manufactured before the specified date as ECE R90 certified as a mark of quality, and reassurance for you.

There still a considerable amount of brake discs which are not ECE R90 certified and yet the quality is still excellent and will meet the same standards as the original equipment, so providing your vehicle was manufactured before the 1st November 2016 there is no need to worry if the discs you have purchased do not have the ECE R90 stamp.

To summarise Brake Discs are a wear and tear item and will begin to wear from the moment they are used, how quick they wear will depend on many factors but how they wear will depend on how they were originally fitted and which pad compound you are using. Brake vibration after use is not an indication that the discs were manufactured incorrectly.