Not sure why you would need brakes for that size trailer. I'm assuming its an open trailer and your hauling just a mower plus small equipment. Generally you only use trailer brakes for larger applications that need additional stopping power. Especially considering your using a Suburban, which has larger brakes, than a small pickup.
If your determined to put trailer brakes on it, your going to need to do the following:
- Assuming the trailer doesn't come with any brakes on the axles, your going to need to perform an axle swap with one that is already pre-designed with brakes.
- Then your going to need to install a converter or brake away box that will supply you with a 6 prong plug instead of the 3 prong your using.
- Once hooked up set your trailer brake box (in truck) to the lowest setting and adjust accordingly.
If it was me, (and I also have a 6x12 in my fleet), I wouldn't waste the time. You won't notice enough difference to justify the time that's involved... But that's just my opinion. Hope that helps