[jcb18]

I actually drained and filled my diffy a couple weeks ago. I bought a rockcrusher cover for about $60 and it came with all new grade 8 bolts. This was the first time I'd ever done this service and I haven't had any leak problems.
My guess is you could find the right sized grade 8 bolts at home depot or lowe's to replace your stock bolts and not worry about breaking bolts again. The previous owner of my rodeo must have lived in a snow belt state because every bolt in my undercarriage snaps if I try to take it off so anytime I take out a bolt (or snap it and have to drill it out) in the undercarriage I replace it with grade 8 if possible.