If you get noise instead of air movement when you turn your fan on you may have a fragged blower motor. Removal of the motor ranges from the sublime (126 chassis) to the ridiculous (108 chassis) but once you have it in your hand you should be able to see why it's not working. It's really a very simple motor/blower cage assembly.

The 2 most common failure modes are 1) a problem with the bearings - are they stuff? or 2) commutator brush wear/failure. This is by far the most common failure more.

These motors really aren't meant to be rebuilt. They're in a riveted cage, so if you want to renew the brushes you're going to have to drill out some rivets and be prepared to find a way to bolt the two halves of the cage back together. This wouldn't bother MacGyver.

The only gotcha is, sometimes the brushes are worn out so completely that the brush holders have gouged a lovely groove in the shaft. You're not going to fix this, throw it away and get a good used, or new blower motor. They're really not that expensive.

The way to tell if your shaft is still ok is to look it it with a flashlight. It should be cylindrical the whole way up. But if the brush holders have messed it up then right where the brushes make contact with the shaft. If it looks like this:

What do you see? A Vase or two faces?

I see a buggered blower motor shaft.

Then you need to get another blower. Yours is toast.

Presuming yours is ok you now need to disassemble it - and best of luck on that - and find a pair of commutator brushes that will fit. Your local starter/alternator place would be a good spot to start looking. MB never meant you to rebuild this so they won't be any help on this.

Did I mention blower motors weren't that expensive new? You'd have to be quite the tinkerer to rebuild one of these things.

Richard Sexton