Okay, I am having issues with the brakes on my burban and have an up coming 4x4 event to go to... so I NEED my burban to pull my junk to the rocks.

I have an 82 burban, 6.2 diesel with the hydroboost brakes, but when I call about the parts everyone says there are two-four different ones it could be... JD3, JD5, JD7, JB5, JB7... no one can tell me how to identify the differences nor which one I should use. I have googled and not gotten much info during my searches.

Any help would be greatly apprieciated!!