Hey everybody. I recently purchased a 1968 Mercury Cougar XR7. The right rear (passenger side) quarter window would not roll up or down (....fairly common problem I guess on these old cars). Anyway, I thought I was going to have to replace the entire window regulator to fix this problem, but doing a little research on this WCCC website, and various other "How To" videos on the internet, I discovered that most likely, all you have to replace is these little inexpensive rollers. So, I removed the back seat, and the quarter trim panel and just like the “YouTube” video shows, the original rollers were completely worn out and falling apart. I installed the 2 new rollers (2 per side) that I purchased from WCCC, and the quarter window works perfectly now. Very cool. Very happy.