Investigation EA01013: 1997–2000 Chevrolet C/K Series

Status

CLOSED

Opened

May 22, 2001

Closed

Dec 15, 2002

Model years

1997–2000

Subject

Vacuum brake booster failure

Component: Service brakes, hydraulic

Summary

Odi upgraded the preliminary evaluation to conduct a full technical analysis, including testing.the testing and analysis shows that a torn diaphragm is a slow progressive type of failure.the tear propagates in a slow methodical manner and braking performance is similar to an untorn unit until the tear exceeds 1/2 inch.odi's testing indicates that tears greater than 1/2 inch required increased pedal effort.however, as the length of the tear increased beyond 1/2 inch, a hissing sound could be heard emitting into the passenger compartment where the master cylinder plunger passed through the firewall. Odi has determined that a safety-related defect trend has not been identified at this time and further use of agency resources does not appear to be warranted.the closing of this investigation does not constitute a finding that no safety-related defect exists.the agency reserves the right to take further action in the future if warranted by the circumstances.odi's complete technical analysis with test data is attached.

An NHTSA investigation looks into whether a safety defect exists. Opening one is not a finding. Outcomes can include a recall, closure without action, or further inquiry.

Model years covered

• 1999 Chevrolet C/K Series9 complaints
• 1998 Chevrolet C/K Series8 complaints