[GaryL]

Some 2500 suburbans came with rear brakes and you could swap them, or maybe try camaro rear brake from the junkyard, they will be the same bolt pattern at least, and have no problem fitting inside the 18" you have, your best bet is to think SCAVENGER

As far as I know, the Camaro's had a smaller bolt pattern than the trucks. I think they are a 4.75 x5 which is too small for our trucks.