Assuming by your rig ... you have 6000# axles. Dexter 12" never adjust LH (K23-458-00) RH (K43-259-00)
Here's a sample vendor
http://www.etrailer.com/Trailer-Brak...er/23-458.html Get the entire assembly as it's all there, cheaper in the long run, and easier to swap out. Unless your brake drums are deeply scored ... 5 bolts, 2 wires each and the swap is complete other than the initial adjustment.