IH 584 right brake inop

[geneP]

I'm talking to a dealer about a 584 that the right brake is not working. The sales guy says they have had it in the shop and diagnosed it as the balance valve defective. They opted not to fix it because of cost. The tractor is priced reasonably and is clean and seems ok otherwise. Does that sound reasonable as the cause? How involved is changing the balance valve if that is the cause?