Bolts for control arm question

I installed a 4.5" RE/ Kevins off road hybrid lift this weekend. I am happy with everything so far. I broke some stock bolts while removing the control arms and was wondering if anyone knew what to replace them with. I had some grade 5, 1/2" bolts that fit pretty good but it sounds like there is some rattling going on up front when I hit potholes. Anyone know what these should be replaced with??

The stock bolts are 9/16".

-Stretch

The stocks bolts are metric(14mm)!

9/16" Grade 8 Bolt will work and is probably stronger and cheaper than what a dealer is gonna charge.

I've had 9/16 grade 8's on my uppers for the last 50,000+ miles

no problemo

x3 for the grade 8 9/16" bolts. Convert to standard! Fight the powers!!