My dremel 300 seems to be leaking black oil Why would this be??

Burnt out brushes.

Dremel has on their homepage an accessory fast finder.

I am sure you can get closer information by searching their fast finder.

Good Luck

http://www.dremel.com/en-us/Pages/default.aspx

Try at eReplacementParts.com : Power Tool Parts and Tool Repair Diagrams

If you need more help post back!
Thumbs and testimonial are welcome!

The on/off button (speed button) can be bad.

Hello
Dremel Is A Very Easy Tool That Anyone Can Use, It Has A Speed Button On One Side That Can Make It Go Very Slow Or Very Fast,,

Hope This Answers Your Question,,

Galway John,,

hello. yes. go to dremel.com and get new brushes for your tool.
ps kindly rate my answer as helpful. thank you. Joe

there is no fuse in this tool, you have another problem and I would go to Dremel.com and talk to their tech support and also download a breakdown for this tool.

try dremel web site for local dealers of spares

Trying to fix a similar issue. The pin that gets pushed in by the button (and returned by the spring) seems to be fine. The hole in the rotating shaft that the pin fits into, however, is in the wrong place, so the pin never goes into the hole! All I need to do is somehow pull the whole front part of the shaft out about 1/16th of an inch, and it'd be fine. I just can't seem to budge it though. Any tricks, anyone?

My Dremel 300 came without any instructions, so I had to puzzle out how to use the circle cutter. None of the images I managed to find on the Web or elsewhere were any help. I directed my attention to the "spike" on the circle cutter, and eventually I realized that it was on the wrong (top) side of the cutter--perhaps for safety's sake. When I removed it and positioned it on the bottom side of the cutter, things became clearer. The next thing was to locate the correct cutting edge. I had never used Dremel before, so I didn't recognize the cutting "bit", since it looked like a drill bit. The final problem was how to attach the circle cutter to the Dremel tool. I couldn't see any way of fixing the cutter to the tool. I thought perhaps there was something missing--a connector, perhaps. Eventually I found a reference on the Web to "removing the cap" on the tool. I hadn't noticed a "cap", but when I gave it a turn, it began to unscrew, so I knew I was in business. Finally II tried the attachment out on a piece of scrap timber, I found that it worked. A simple instruction manual would have saved me a lot of time. Also, I now discover that the Dremel 400 would be much more useful than the 300. Dremel don't seem to be very customer friendly. I can access the US site, but the UK and Germany website won't let me in!