GMC · Canada · High
GMC Series 53, Classic: Brakes
Affects GMC Series 53, Classic · 1985–1987 — about 568 vehicles.
The hazard
On certain vehicles, the brake interlock shuttle valve assembly could, under a heavy (panic) service brake application, fracture or fragment the internal shuttle piston resulting in a complete loss of rear braking. A reduction of braking ability at a time when maximum stopping distance is required, could result in a vehicle crash without prior warning. Correction: A new two-way check valve will be installed in the interlock valve assembly.
What to do
Contact your dealer; the remedy details were not included in the filing.
Critical — crash/injury risk now
High — injury risk; see remedy
Moderate — fix at next service
Low — minor / informational