After 6 years and 60K+ of towing (including 3 months in Alaska) with the haha decided to take it apart to have it sandblasted and repainted. No need to post photos as the ones on the "ultimate haha user guide", page 37 post 505 show enough.
Did a complete tear down and found:
No water or dirt inside so only replaced grease seals and repacked bearings.
Replaced upper dust caps only for cosmetic reasons since doing a repaint. Cleaned and reinstalled two of the old ones for the bottom.
Replaced grease fittings (zerks)-the plunger that holds the spring bars in place did have a little wear but had much more life in them. Wasn't necessary to replace but since I had it apart figured I would and saved the old ones for spares.
Replaced the spring bar U-brackets. The elongated holes which the pin slips through to connect the strut assembly to the spring bar enlarged due to wear and/or compression. The hole enlarged to 1/8th " closer to the edge. On the new brackets, the hole begins 3/8th " from the top edge of the bracket but on the old brackets, the hole wore to 2/8th " from the edge. This is the only part I felt needed replacing because of the wear and stress by the spring bar tension and probably is something haha owners should add to their frequent checklist. I don't know how much that hole can enlarge before it poses a threat of failure or effects towing.
The twin bushing located on the bottom of the hitch box, where the ends of the spring bars insert, had some wear on the interior ends but not as much as in the photos mentioned above. I called Hensley and was told as long as the spring bars stay inserted no action is necessary.
Replaced the collar with set screw which holds the strut assembly to the frame bracket only because the set screws were rusted, another cosmetic thing.
Replaced the 4 shear bolts because of rust.
It was an easy tear down, no special tools or complicated parts. As said in previous posts, if you can do wheel bearings you can do this, although after doing it and inspecting mine, I'm not sure it is necessary. I think if you pop off the upper and lower dust caps and you can see no water is getting inside and the grease looks clean, you'll be fine. My son-in-law sandblasted the parts and repainted them a shiny black used for farm equipment which should last longer than the original paint job.
So, after 6 years and a lot of miles the Hensley was in good shape. The only necessary fix, and only in my opinion, was replacing the spring bar u brackets and getting the whole package painted.
Next project, brakes.