Missing plastic part
Hello there. At first glance this pivot shoe looks like the Certainteed 15-192. However I suspect you might have a Simonton window. We have found the 15-192 does not fit these windows correctly. Some customers have made it work by rubbing down the alignment ridges on the face of the replacement shoe, but others have reported otherwise. if you do try this, note that modified items cannot be returned for refunds.
Because of these difficulties, we devised a substitute solution. The 15-259 Pivot Shoe can fit this window; however you'd also need to replace the coil balance springs further up the window track with the Series 159. The video below shows how to do this.