Vehicle recall 21V953000 · December 9, 2021
Mack Terrapro (mru), MRU and 2 more models
A brake control valve air leak into the attached exhaust hose can create excessive back pressure, causing the parking brake to release unexpectedly.
Source: NHTSA data as of September 22, 2026. Last refreshed Sep 23, 2026, 2:43 AM UTC.
- Summary
- Mack Trucks, Inc. (Mack) is recalling certain 2008-2019 TerraPro (MRU) and 2019-2022 TerraPro (TE) vehicles. A brake control valve air leak into the attached exhaust hose can create excessive back pressure, causing the parking brake to release unexpectedly.
- Consequence
- The unexpected release of the parking brake may allow the vehicle to rollaway, increasing the risk of a crash.
- Remedy
- Dealers will remove the exhaust tube and fitting from the valve, free of charge. Owner notification letters were mailed February 8, 2022. Owners may contact Mack customer service at 1-800-866-1177. Mack's number for this recall is SC0433.
- Notes
- Owners may also contact the National Highway Traffic Safety Administration Vehicle Safety Hotline at 1-888-327-4236 (TTY 1-800-424-9153), or go to www.nhtsa.gov.
Recall details
- NHTSA campaign
- 21V953000
- Reported to NHTSA
- December 9, 2021
- Filed by
- Mack Trucks, Inc.
- Manufacturer campaign
- SC0433
- Owner notification
- February 8, 2022
- Vehicles potentially affected
- 20,668
- Initiated by
- NHTSA’s Office of Defects Investigation
- Components
- Parking brake
Vehicles covered
As listed by NHTSA. A recall usually covers only some vehicles of each model and year, often a production date range.
Has your Mack been repaired?
Recalls here come from NHTSA’s records for the model and year. Not every vehicle of a model is included in every recall, and this site can’t see whether a repair has been done. Only a VIN lookup can tell you that.
NHTSA’s VIN search doesn’t show recalls that were already repaired, recalls more than 15 years old, or some small manufacturers’ recalls. A Mack dealer can also check your VIN. Recall repairs are free.