What you are saying doesn't make sense. The backing plate should be to the outside of the where the bearing carrier or seal is. The only part that should even be close to the seal would be the base of the brake drum itself. That is why more than likely no one answered you.
Nicholson 500x (Project)
Nicholson 185s
Nicholson 110 (That takes an atc70 tank)
Ascott 500 head/350x (Project)
Homebuilt Racer Chromoly Suspension 110 (Ragin Runt)
PK Racing Suspension 70
A+ Inc Suspension 70
AWS Aluminum 90 frame
Hi Performance ATC Suspension frame rd350
Hi Performance ATC Suspension frame 90