8 out of 10 flipper rebuilds i do need new bushes, if the hole in the bushes are oval due to wear then even with a flipper rebuild kit won't get your flippers running %100 (some kits don't include bushes)
Also your flipper optos must be %100. I have come across many flipper coils running hot and week due to weak or faulty optos.
last make sure all the pins on the flipper board connectors are clean and not pitted.
