Hi, i am in the process of taking me rear wiper off me 172, got the wiper arm off, took out boot lid lining and took out bolts that hold on the wiper motor, but the shaft dat drives from the motor to the wiper will not come out, cannot work out y it wont come out because seems loose and cant c any other bolts, anybody got any ideas or know of any hidden fixings that i may not have seen that have to be removed first.