Replicator 2 extruder replacement with no overheating issues v2

Trying to improve the extruder mod v1 loaded last month http://www.thingiverse.com/thing:60574 I decided to make a new and cheap design using a 9 mm diameter bearing and one clothespin that everybody has at home. The spring of the clothespin has the same internal diameter than the extruder default bolts si it is "perfect.