Replacement power brake booster. Make sure that your brake system is at optimum performance by installing one of these dual-diaphragm boosters. This is also a great upgrade for older boosters, as it increases your braking pedal pressure and helps you stop sooner. OEM correct for 1983-1991 FSJ's, but will fit earlier years. Note that the dual diaphragm boosters use the later model plastic-reservoir master cylinders.
Fits: 1983 Wagoneer, 1983 Cherokee, 1983-1988 J-truck and 1984-1991 Grand Wagoneer