Manitoba Airbrake Practice Exam 2024 - Free Airbrake Practice Questions and Study Guide.

When there is grease or oil present on the brake lining, it can cause abnormal brake behavior. This can include a longer stopping distance, decreased braking performance, and even a loss of control of the vehicle. This is because the oil or grease creates a slippery layer on the brake lining, making it difficult for the brake pads to grip onto the rotor. This also leads to inconsistent braking, making it unsafe for the driver and those on the road. Therefore, regular maintenance and cleaning of the brakes are necessary to prevent any oil or grease buildup and ensure safe braking. Option A is incorrect because brakes squealing is often a sign of worn brake pads, not necessarily due to grease or oil. Option B is incorrect as grease or oil would not improve braking efficiency. Option D is incorrect as brakes do not have the ability to automatically adjust if there is grease or oil present on the lining.