You have a dual axle trailer. So, you will need 2 left side and 2 right side brake assemblies if you decide to change out the complete assembly. If just replacing the shoes, you may be able to find these at an auto parts store. Dexter would be good for the part numbers.
Shoe/Lining
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Your brakes on the RV are electric brakes. There are 2 wires coming out of the axle tube at each wheel, connected to the back of the plate. The link I gave you has the brakes for your rig. If you are going to change the wheel assemblies, contact Dexter for the correct parts would be the easiest since this is your first time buying parts.
Since you are going to have the tires off, might as well as do a bearing repack job on it. The bearings and seal you can get at an auto parts store. Take the old set with you and have them match the numbers on the parts.
dexterindex.com
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