There are indeed two wheel cylinders per rear wheel, on any 280 series (1 1/4 ton), & up. I haven't done any brake work on my trucks in several years, so I can't give you a price. There's a few guys here that i'm sure will step in, that have done brake work recently. This truck will be at least a 2 ton. There were no 1 1/2 ton rated GMC COE's in the years '47-'54. Check the ID plate in the driver door jamb. If it's 16000lb. gvw, it's a 2 ton.
