Summary
The GMC C7 has 7 recalls covering the 1979–1990 production run, with the most serious recent issue being a 1990 model year recall where front air brake hoses can chafe against inner fender extensions, rupture, and cause a complete loss of front braking.
The 1985 model year has two recalls. The power steering assist cylinder mounting bracket bolts can loosen, allowing the cylinder to detach and restrict steering while also severing the front brake hose, which removes front axle braking. Separately, 1985 models with a transmission-mounted internal expanding parking brake can develop a cracked actuating lever cam that gradually loses its clamping force, reducing the vehicle's ability to hold on a slope. On 1983 models, severe brake chatter can crack the front axle brake chamber mounting brackets at the weld where the cam tube meets the chamber support, which can cause loss of front wheel braking and restrict steering control. The 1983 model year also has an issue where a carbon steel check valve spring installed in the dual compartment air reservoir can corrode, eventually failing the reservoir and compromising air brake performance. Going back to 1980, certain trucks with a specific combination of master cylinder and frame-mounted brake booster can draw air past the seals and into the brake system, reducing braking ability without warning. The earliest-production recall affects 1979 trucks sold to a fleet operator in Ontario, where a misrouted positive battery cable can rub against the right front brake tube, damage the line, and cause brake fluid loss.
