My laing cir pump keeps breaking down I have rebuilt the head three times in two years. Anybody know whats going on?

The laing's usually get messed up because of too much solid matter in your water (too much chem's). Since you've replaced the front end of this thing several times, did you ever notice a lot of white gunk all over it? Or are the rotors getting warped or? Somtimes, even the back end can cause a repeat problem with the rotor not spinning up perfectly, and over time you can end up with a rotor that deforms... repeatedly. In this case, the best thing to do is just buy a completely new pump.