The 1979 GMC C Series has two recalls, both involving the brake system and both carrying the potential for brake failure without warning.
One recall covers vehicles with vacuum-assisted disc/drum brakes, where the brake booster can develop fatigue cracks severe enough to cause brake failure when a hard, sudden stop is needed. The other affects certain C20 pickup trucks, where front brake hoses may have been installed with fittings oriented incorrectly, causing the right hose to rub against the upper control arm or leaving the left hose twisted at its frame connection. Either condition can wear through or stress the hose until it fails, resulting in a loss of front braking.