40 hub rubber ring

[79er]

doing a total nut and bolt restoration on my 79 40 I drove off the lot in 80. Currently in the birfields. When disassembling the hub there was a rubber ring on the side that the brake I found after I removed the rotor. After everything was cleaned and painted and upon installing new OEM rotor it doesn't fit between the two. Can't figure out where it should go. Any help?

 

[peesalot]

IIRC that goes on the lip of back plate and rides on the silver ring on the outside surface in pic, keeps dirt outa rear hub bearing.

 

[locklaw]

That rubber is part of the spindle seal, you are missing the steel portion (it should be one unit) -

 

[79er]

Ah, makes perfect sense now!!!! It rusted away. I have the kit so im good. thanks a bunch