As usual, click any photo to bring up a larger version.
Here is my free shop vac. About six to eight months ago I found this on the curb on trash day. I figured it must be broken (why else would someone throw it out?) but I grabbed it anyway, so that I could salvage the attachments. In particular, I wanted the hose.
Yet when I took it home and plugged it in, it worked! There was a bit of a rattle, but only once or twice. Since then it has worked well for my light hobby use.
Six months later, the rattle came back with a vengeance. You can hear it at the beginning of the above video. It started making a nasty rattling/squeeling noise, which really sounded like the bearings or something inside was falling apart.
With nothing to lose, I pulled off the motor unit and set about disassembling it. Fortunately it is just held to gether with Torx screws, which are pretty easy to remove.
As a side note, I really recommend that everyone get something like this 99-piece Not-So-Common Bit Set for their shop. Mine is from Lee Valley, and no they aren't paying me to say that, but I'm open to offers...
In all seriousness, this kit will sit on your shelf unused most of the time, but when you suddenly are faced with some weird type of fastener, this will save your bacon.
The motor housing came apart pretty easily, revealing the small and very dirty fan assembly inside. So I gave it a quick brush and wipe to get rid of the worst of the dust.
I was pretty amazed at how small the actual fan/blower was. I doubt it is even 3/4" thick, and yet it moves a large volume of air. I guess that is due to the high RPM. (I have a software degree, I know practically nothing about this type of engineering!)
There were no apparent broken pieces, so I just set about lubricating the bearings with some three-in-one light machine oil. I addes some drops, spun the motor, turned on the motor, and repeated the process three or four times.
I opened up the last part of the housing and looked inside as well. Nothing was broken there, nor was there anything inside to lubricate. The motor itself is not that big.
I wanted to lubricate the bearings on the other side -- the part under the fan -- but the bolt holding the fan to the shaft was extremely tight, and slightly rusted. I did not want to risk breaking anything, and the motor was already sounding much better, so I stopped. Instead, I just dripped some oil between the fan and the motor housing, and used a thin shim to guide the drops so that they (more-or-less) ended up on the shaft of the motor.