So ended up purchasing a Harbor Freight DA this past weekend and immediately started modifying / improving the DA to address some identified weak points. I took some pictures along the way to hopefully help others. I can’t take credit for any of these mods as I’ve either read or seen these things posted in different posts while I was researching the HF DA.

If anyone knows of any more low cost "improvements" please feel free to post

Weak points and mods:


Weak backing plate – Purchased/replace backing plate with a high quality 5” plate. (shipped and in the mail so no pic)

Awkward switch location – Relocated switch to top by rotating body

Instructions:
1. Remove 4 screws which attach the metal head to the plastic body.
2. Carefully pull back plastic body ~ 0.25 – 0.5 in.
3. Rotate 90 degrees and reinstall screws



If you accidentally pull the plastic body back too far, which unfortunately I did, you’ll need to remove the bottom half of the plastic body to pull the brushes back. To remove, brushes unscrew bottom screw by the power cord then pull off bottom plastic cover. Unscrew / remove the brush assembly then reinsert the top half.





Noisy – Cleaned and repacked gears

Instructions:
1. Remove red hand grip
2. Remove backing plate
3. Remove 4 screws which hold the upper and lower metal assemblies together.



If you have issues unscrewing use vice grip to break the screw(s) free. I purchased M4 x 0.7 x 16mm screws (total cost ~ $1.00) to replace cheap screws. Also added the convenience of using allen / hex wrench instead of phillips.



4. Clean out existing grease



5. Repacked with high quality grease. Use extreme pressure / high temp grease. I used Mobil 1 synthetic grease I had laying around. Sorry no pic hands were a mess and didn`t want to touch phone/camera
6. Assemble two metal halves
7. Run at lowest speed working up to highest to remove excessive grease.
8. Clean service hole and cover with duct tape or other. Some have used 0.25 in plastic plug. I used aluminum tape I had on hand.
9. Reinstall red hand grip

To do:
Short power cord – Replace power cord with 25” 16 gauge power cord – Need to find “cheap” power cord to make this mod worthwhile