Final answer:
The statement that a motorist should test brakes by pumping them after driving through a water puddle is generally true. It helps to dry wet brake pads, ensuring that braking efficiency is maintained.
Step-by-step explanation:
When driving through a water puddle, a motorist should test his brakes by pumping them. This is because driving through water can cause the brake pads to get wet, which might reduce their effectiveness until the pads dry. Pumping the brakes helps to generate heat through friction, which assists in drying out any moisture accumulated on the brake pads or discs. This advice is especially relevant for vehicles with older braking systems; modern vehicles have different mechanisms to clear water from the brakes automatically, but it can still be a good precautionary measure.
Hydraulic brakes use Pascal's principle, where the force a driver exerts on the brake pedal is increased through a lever and a hydraulic system, ensuring that each wheel cylinder receives the same pressure and generates the same force output to stop the vehicle effectively. Knowing this, it's crucial that brakes are in good working condition, particularly after they may have been compromised by water.