Not sucking

Question

We have an Oreck XL and today it is blowing out dust instead of sucking it up. I just replaced the belt and about 6 months ago, we took it to our Oreck dealer and had it rehauled. I opened it up to check all and it all looked fine. Then I tuned on the machine while unzipped and noticed that the bad does not inflate as it used to. What can I do?Thanks,[e-mail]