This has been pretty comprehensive instruction in rebuilding a model D. I didn’t initiate this thread, but I’ve certainly benefited from all this information. And to this group, I’m very grateful.
Do yourself a favor and do not follow the directions of the guy doing the YouTube video on page one of this thread.
Does it make sense to anyone that you have a hub that was originally designed with an "oil hole/cap", and that you should pack the hub full with thick grease, to the point it's oozing out of the oil fill hole? And while your at it, forget the 90-weight gear oil also. Just use a very lightweight grease, White Lubriplate, or the common lightweight disc brake wheel bearing grease you find in any auto parts store is fine. Just grease the bearings and wipe a light coat on the moving parts like the driver threads and the clutch and retarder spring. Use some 30-weight motor oil on the disk's, and you're done. If you pack it full of grease, you will have a ton of drag between all of the disk's making it hard to ride. All of that grease is going to work it's way out of the hub eventually (there's NO grease seals) and it will be a frigging mess. God help you if you have whitewall tires. And another thing, be very careful with the Brake Clean, or Carb Cleaner around any painted surface like your newly painted rims or getting any on your whitewalls. The original New Departure replacement disk's were packed in shipping cosmolene for rust prevention, we washed them and oiled them before service.
I'm assuming that since you guys are working on bicycles you have the basic sizes of cone wrenches. The New Departure, NK, Mattutuck brakes use a 9/16" and a 5/8" cone wrench. The brakes come apart and go back together from the driver side. You put the entire brake cartridge together and slip it in from the bottom while you're holding the wheel horizontally. Then put the left "lock nut" into your vise to hold the wheel. Install the last bearing, drop in the driver, the adjusting cone and lock nut (no washer). This will allow you to make your final fine adjustment while the wheel is still in the vise. The correct adjustment for a "ball bearing" is just a very slight amount of play, in the tightest spot, so you have to rotate the wheel and work the brake operation to make sure you do not have any tight spots. Roller Bearings need a little pre-load adjustment, but Ball Bearing need a very small amount of free play adjustment. If you "over tighten" your cone adjustment, it will come out all pitted like the cone in the YouTube video.
Do not over grease.
Lightly oil the Disk's.
Install the brake assembly "as a cartridge" from the left side of the wheel.
Do not over tighten your adjusting cone bearing adjustment.
Nothing has changed on servicing a New Departure hub in 100 years.