I recently replaced a bunch of pulleys in my 04 Blazer including a new gatorback belt. I didnt have a squeak before as I was just doing preventative maintenance. I now have horrible squealing. This is nothing different from other posts on here about squealing problems. I do have a question though. I bought a new AC Delco idler pulley. There was a note on the box that said it had a sealed bearing and not to use the dust cover. I replaced the old pulley with this new one and put everything back the same (spacer in back, bolt, and front washer thing). What exactly is the dust cover? Is it the front metal washer thing that covers the bearing? I removed this the other day thinking I may not need it and now there is some play in the idler pulley. Do you need this washer thing or not? Please advise. Thank You.