I have a HF DA too that I got on Mother's Day. I think it was $59.99 and I had a 20% off coupon, so I paid $48 I believe. I bought a 5" backing plate so I can use 5.5" pads.
I would like to regrease mine as well, so if anyone knows where the directions are, post it please.
I have the directions from another thread, with pictures. I made into a Word file, but will try and get uploaded, this was not mine. I was able to do the process, which tool all of about 45 minutes.
1.) Remove the backing pad. Find the wrench that came with the unit and remove it.
2.) I was able to remove the (4) screws on the head with a good phillips head screw driver. Put some pressure on it so you don't strip the screws out, but can be done pretty easily.
3.) Pull the head off and clean out all of the OEM grease. I was able to just wipe out the a towel, then went back and cleaned with brake clean, to get it all out.
4.) Install new grease, I went to O'Riely's and bought their Red High Pressure Grease, about $5-$6, you will only use a little bit.
5.) Pack the head and grease the bearing on the shaft.
6.) Reassemble, wipe everything down and retorque the screws.
There is a bleeder hole on the back side of the head. Make sure you remove the red cap. Turn the unit on very slowly at first and you will purge some of the grease. Slowly work the speed up to operating speed. Do a final wipe down reinstall the red cover and your done.
I hope this helps. Others have removed all the pieces inside the head, but I did not see a need, just be careful when removing he screws and you will be good.
Let me know how it works out. Mine was much quieter afterwards, worth the little effort.
Bill