Al,
When replacing a wheel hub oil seal, I always remove the oil seal and take it with me when buying a replacement, therefore I have never written down the various part numbers. To remove the drive hub, you will need a 4 inch socket to remove the spindle nuts. I use a 3/4 inch drive one on a 3 foot long ratchet, and I have never had a problem with the lock nut. However if you are not familiar with drive axle repairs or do not have the proper tools, you might consider having it done by a professional, but only one who is familiar Meritor ADB brakes. Very few trucks ever had Meritor ADB brakes, so truck mechanics have rarely, if ever worked on them. They were mostly used on Fire Trucks, Tour Buses, and RVs.
When it comes to brake pad part numbers, there are many options depending on whether you want pads for one or two wheels and how severe your operating conditions (temperature) are. Also Meritor changed their part numbering system a few years ago, so there are still a few of the old part numbers around (S2R7017173). For your coach there are 3 service levels of brake pads in an axle set (2 wheels) that run from Kit15625PM, Kit15626PM, and Kit15627PM with the higher numbers being for more severe service conditions and at a higher price level. The single wheel kits are Kit15615PM, Kit15616PM, and Kit15617PM, if available.
When it comes to caliper lubrication, my suggestion would be to lubricate all calipers, using the proper grease, and following the exact lubrication instructions listed in the Meritor service manual. These lubrication instructions will purge some of the old grease and lubricate the piston and shaft to insure proper operation. I lubricate my Meritor calipers about every other year. This schedule is about right for the drive axle and probably a little excessive for the front and tag axles since Meritor states that the calipers should be lubricated twice in the life of the pads and I drive about 15,000 miles annually on average.
Also, when servicing your Meritor ADB brakes, my suggestion is to always install caliper return springs as per the Meritor Technical Service Bulletin, if they have not already been installed or if they have been damaged from excess heat. The part number for the spring kit for one wheel is Kit15018, and they are only sold per wheel (2 springs), so you will need 6 kits for a tag axle coach.
Gerald