the outer bolts by the steering pivots didn't have much pressure on them like the 2 center bolts for the bearing carriers but they cracked as well. i think Thin PLA under stress will crack like ABS. i figured beef up the thickness wall a little and see how it holds up.
if you open up the bearing carrier tolerance you have to be careful not to go too much as then the gears will hop under load.
right now with the cracks the axle housing is staying together. but i did see horizontal cracks forming in the center section.