Here's where the new second-generation design helps the installer. The copper air line now enters the carrier on the left side near the ring gear. Previous designs have a separate seal housing with two U-rings for sealing and could be damaged on installation. The new design has the seal housing and O-rings factory installed. On the 8 1/4 unit, the carrier is set in place, then the carrier bearing ring adjusters are installed, and then the carrier caps. The bolts are only tightened down finger tight so the backlash on the gearset and the bearing preload can be adjusted.