On my raider I noticed that the rear backing plates for the rear brakes are rusted and I can find any place that can get new ones is there anyway I can use backing plates from a Dakota or a full size
Did you try Mitsubishi?
I looked into ones for the montero but every place and website I look into dont have them or they are a discontinued item
Have you tried to get some through a auto salvage yard?
To extend this question, are they just rusted or are they rusted through? If there just rusted, you should be able to clean the rust off them and paint them.
How about repairing them with POR 15
They are completely rusted through but I'll check salvage yards