Dryer Heating Issue

I have a Whirlpool ler8858eq1 dryer that stopped drying last week. I toook the heating element out of it and checked it and its fine as well as the two electrical parts on the heating element housing. I checked all of the wiring and it was all fine. I put it all back together and it began heating again like there was never a problem. Just last night it stopped heating again after running for about an hour drying some sheets. The drum turns fine but just no heat. Any suggestions on where to start?

Thanks
Andy