GM says it needs to bleed the brake systems of 230,000 cars.
Some of the recalled vehicles have rear brake caliper pistons that have hydrogen gas trapped inside that could be released into the brake systems. ZF, the manufacturer of the brake pistons, didn't properly temper and chrome-coat the pistons, causing hydrogen gas to remain trapped in the bodies of the pistons.…
keep reading article "Excess Gas Buildup in the Brake Caliper Pistons of Regal and LaCrosse"