NHTSA Probing GM Truck Brakes

The National Highway Traffic Safety Administration (NHTSA) has opened an engineering
analysis of the vacuum brake booster on 1997-2000 General Motors C/K full-size pickups,
which are very popular among trailerists. The investigation, which involves the brakes on
3.9 million GM pickup trucks, was triggered by more than 200 complaints of brake
malfunction. The brake booster uses the vacuum from the engine to increase pedal force.
When it fails, a significantly greater force is required on the brake pedal to stop. Some
drivers say they heard a hissing noise from the vicinity of the booster when they stepped
on the brakes, which is a sign of failure. NHTSA said it found that GM had replaced some
17,000 vacuum brake boosters under warranty. At least 25 crashes with eight injuries are
linked to the problem.