Why do my wheels vibrate when I brake?

Thursday November 21 2019

Mitsubishi Pajero

Mitsubishi Pajero  

By Paul Kaganzi

Hi Paul, I drive a Mitsubishi Pajero and when I apply the brakes when driving fast the wheels shake violently. It is scary. The suspension and bushes have been checked and are fine. What could be the cause of this problem and how can we solve it? Claire

Hello Claire, what you described sounds like brake judder. This is violent shaking or vibration with noises when you apply the brakes or try to slow down. This sensation usually transmits from the brakes upwards through the suspension to the steering. This unnerving feeling can cause panic to a motorist.
Brake disc rotor run out is the excessive wobble of wheels moving unilaterally. There are several causes of this situation. Build up of rust and dirt on the wheel hub or warping, which reduces contact between the brake disc and wheel hub. Severe brake disc overheating will cause judder or disc rotor run out. Disc rotor overheating can be caused by excessive or frequent braking or use of ‘cheap false economy’ brake pads. This sort of brake abuse will cause scorching of the disc rotors at different points where the discs will even turn blue. These discs are beyond redemption and should be replaced. Variation of disc thickness is another cause of wheel judder. This can be caused by frequent harsh braking or failure to run in new brakes to evenly, which leads to uneven pad or disc surface. Pressing brake pedals for a long time while the vehicle is stationary as well as rust and dust accumulation will cause deposit build up or imprints which cause uneven surface at intervals around the disc. As you apply the brakes the discs will judder as the brake pads engage uneven disc surface. You can have this resolved by a mechanic who will examine the disc rotors carefully to decide whether they ought to be skimmed to even the surface on a lathe machine or outrightly replaced with new ones. That should fix the problem.