Hello Paul, I own a Raum 2005 model. Why does my car steering vibrate a lot when l hit the brakes when driving at high speed? Stephen.
Hello Stephen, a vibrating steering when you suddenly apply the brakes at high speed is usually caused by unevenly worn out or warped brake discs. Brake discs are large metallic rotors behind the wheels. They rotate along with the wheels so when brake pads clamp on them, they help to stop your car. Brake discs get very hot during braking due to friction.
This can make the metal vulnerable to wear, albeit unevenly. Uneven brake disc warping or wear is usually caused by braking with worn out brake pads that engage the very hot disc more on some patches of its surface. These uneven patches cause a judder when you brake at high speed.
You can find a technician to dismantle the wheels and measure the surface of the brake discs using a micrometre screw gauge. Spinning the brake discs and feeling their surface can also help you see the imperfections. If the disc width is still within acceptable limits, consider skimming the uneven surface with a lathe machine. To replace, make sure the brake discs are tightly fastened to the hub.
Do some wheel balancing to rule out bent rims too in case the discs check out. To avoid brake disc warping or uneven wear, avoid driving long distances downhill with your foot jammed on the brake all the way. Try using engine braking by shifting into lower gears (manual transmissions) or selecting lower gears 3 or 2 (automatic transmission). It takes a bit of skill and quick thinking to use engine braking or shift to electronic manumatic gear shifting in newer cars, but it is worth a try.