Originally Posted by FidelCastrovich
.. now probably has a ruined BB interface on the left crankarm.
Why would the BB be ruined? The axle is steel; cranks are much softer metal. The only time you need to replace a non-integrated BB is when the bearing surfaces are shot.
Q2 - Recommended spindle length 113/118. Right now i have a 122.5 spindle. How do i know which spindle length BB to order online?
The required spindle length is determined by the particular crankset and the rear chainline. And sometimes getting the right fit just comes down to trial and error.
Read and heed the post above about maintenance.