USE OF THE AIR HORN CAN CAUSE THE AIR PRESSURE TO DROP BELOW 85 PSI.
Consequence & remedy
Consequence: IF AIR PRESSURE DROPS BELOW 85 PSI WHILE THE VEHICLE ISBEING DRIVEN THE REAR BRAKE SPRING CHAMBERS WILL START TO APPLY CAUSING THEREAR BRAKE DRUMS TO OVERHEAT.
Remedy: INSTALL PRESSURE PROTECTION VALVES IN ALL AIR HORN CIRCUITS.
Model-level recall history does not show whether a particular VIN is affected or has received a repair. Check a VIN with NHTSA ↗
NHTSA investigations
1
PE88068 · Various Brake Problems
Opened Jun 28, 1988 · Closed Nov 7, 1988
Status: closed (inferred from source dates) · Service Brakes, Hydraulic
SUMMARY: RECENT ROCKWELL REPORTS IDENTIFIED THE FOLLOWING ADDITIONAL CONCERNS: A: INSUFFICIENT AIR PRESSURE DUE TO INADEQUATE AIR COMPRESSORCAPACITY; B: AIR HORN PLUMBED INTO AIR SYSTEM WITHOUT PRESSURE PROTECTIONVALVE; C: BRAKE IMBALANCE CAUSED BY BRAKE PROPORTIONING VALVES WHICHREDUCE THE FRONT BRAKE PRESSURE. THE ABOVE PROBLEMS MAY RESULT IN HEAT CHECKING AND CRACKING OF THE REAR BRAKE DRUMS.
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