I think i already know the answer to my question but i thought i would try anyway i have a girl and my friend has her step brother they have same mum but the boys dad is my girls uncle is the blood line to close to bred. what is likely to happen if they do bred i do not want to sell them i would of kept them just so she could have had one litter.Thanks for your help

A breeding this close should only be done by a very knowledgeable and experienced breeder since by breeding this close you will be doubling up on any faults(ALL DOGS HAVE FAULTS) and hence you need to make sure that both dogs are as close to 'perfect' conformation and health wise as possible.
It really is not a good idea for a novice breeder.
Archer

its not too close IF all is well,but could be too close for a novice breeder. what faults are in the line?