When doing one of my checks I noticed that the center cap seals for the hub bearings were breaking down, cracking/dry rotting. I wanted to make sure that I had a good seal as moisture can degrade bearings and shorten their life. So I called DRV, Moryde and Kodiak to find out a part number or dimensions for that seal. I was told the ONLY way to get it was that I had to buy a new cap for $30 some dollars per cap plus shipping. I went to every local Auto parts store and found a close match that I posted up on here. But it was still just the same plain black rubber seal. I wanted something that could hold up to the heat with out breaking down. After ordering several seals to find the correct one, I finally have a good match that I just received today. I will be installing these with in the next couple of days. I will also post an update in a year with how they are holding up. But for 30 times less then buying a cap assembly, it was a no brainer. I ordered 8 seals so I will have a spare set as a back up. This link is where I bought them from,
-230 BV75 Brown FKM (Viton, Fluorocarbon) 75 Duro O-Rings [BV75230] : The O-Ring Store LLC, We make getting O-Rings easy!
Happy and safe travels.