Idler Pulley Failure

[lucoche]

Originally Posted by Homeoboxter

Wow, thanks for sharing that. I rebuilt all my idlers with new bearings, but those were in much better shape, and only 100k in the car. Maybe yours had been rebuilt too somewhere in the past and this one got a little crack due to pressing the new bearing in and just gave it up now. I heated up mines and cooled down the bearings when I installed them to minimize the chance of damaging the pulleys, because they are indeed made of very thin material.

I think that you are exactly right about the last detail that was missing to my investigation! Alot of people will not seat on the right surface to press the bearing in and/or out. And on the pictures we can clearly see that the breakage would be pretty similar if we would voluntarily seat on the outer ring and apply big force on the bearing insertion’s axis.

I also use the frozen bearing and slightly heated housings (because of aluminum parts) for the wheel bearings jobs to reduce the interference fit and make pressing work a charm! Thanks for your reply! Porsche should have my parts tomorrow!