Wow, thats an old Oreck. You can't really break an Oreck, every part is replaceable, even the motor, hood and screws, so an Oreck is an good investment.
Okay, 3 things could be going wrong. You might have an old fan chamber which could lead to the fan hitting it and making the bad noise. Replacing it could fix it. The next thing is the motor. You say your lubricating the bearings. You can't really work on the Oreck motor, so you can also replace the motor. About $100, but most likely it the first thing I explained about the fan. The last could be you need a brush roll, old ones get loud when the bearings get filled if hair. It's just better to get a new one than fix the old one.
Your Oreck is a very reliable machine and really can't be broke. Just remember to change the belt every 6 months and keep it in good shape. Hope I helped.
Nathaniel, February 2010
