NissanPartsDeal.com offers the wholesale prices for genuine 1991 Nissan Hardbody Pickup (D21) parts. Parts like Breather Piping (For Front Unit) are shipped directly from authorized Nissan dealers and backed by the manufacturer's warranty. Parts fit for the following vehicle options. Engine: 4 Cyl 2.4L, 4 Cyl 2.5L Diesel, 6 Cyl 3.0L. Grade/Trim: Basic, DX, GST, SST, ST, STD.