Just about to replace the main bearings in my 89 4runner 3.0 V6 and seeing if anyone had
any general tips on it. Only one of them is bad on the #4 piston but comes in a set and should
probably replace them all anyway. Haven't taken the bottom of the rod off yet, i got the two nuts
but the bottom is being stubborn on coming off. Are there bearings that are thicker to compensate
for the wear (if there is any) on the crank?

 

I went thru this a few years ago with another toyota. If its knocking the crank will need work. They use really hard bearings in their engines (thats why they run so long) and the crank will wear with the bearings.