Repeatedly Clogged Printrbot Simple Extruder I have a Printrbot Simple Metal. The extruder is getting clogged all the time. I went through the process demonstrated here multiple times already. Heatting the extruder and pushing different tools all the way through to make sure it is completely clear. 
Every time I get a clear flow of PLA, and after a few minutes the extruder motor starts clicking again. At that point, it is even hard to push in the filament by hand.
I replaced the tip already, but this didn't make any difference. I also tried few different filaments, all of them worked perfectly before.
It feels like stopping the flow even for about 30 seconds would cause it to jam.
I had a similar issue on my Printrbot Simple Metal. I believe my problem was initially caused by clogged nozzle which I replaced, however the jamming persisted. I can't say for sure that it was acting exactly as you describe but I think it may have been similar. I noticed that the little red insulating sleeve was pushed up higher than it was when I got it from Printrbot. When I lowered this my problem seemed to go away.