NHTSA investigationDP78021
Investigation DP78021: 1976 Mack Mack
- Status
- CLOSED
- Opened
- Jan 19, 1978
- Closed
- May 26, 1978
- Model years
- 1976
Subject
121 braking system, brakes lock up
Component: Service brakes, hydraulic
Summary
121 braking system, brakes lock up
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.
About this data. Data from NHTSA (ODI) complaints, recalls, TSBs and investigations, updated Oct 28, 2026. Complaints are unverified consumer reports and may be duplicated or inaccurate.