I have used Bearing Buddys on boat trailers and on a 1970 21ft Streamline single axle
we had years ago.
I never had any leakage when I used their special seal, and never had any bearing problems on either application.
The biggest downside was when I had to pull the hub to service the brakes
, the entire hub bearing cavity was packed with grease. The result was a bit of a mess, but not a terrible mess.
What I did was to stick a paper towel tube over the spindle as soon as the hub was pulled and secured it over the end with a C-clamp. After re-doing the magnets and shoes and cleaning everything up I just pulled off the paper towel tube, checked that there was no dust or debris in the grease coating the spindle and put the hub back on.
I just don't remember it being any big deal. I'm also beginning to think the Scamp
parked outside might just start wearing a set of Bearing Buddys in a couple of days!! It might just be a Scamp's way of thumbing its nose at conventional wisdom. Those Scamps have personalities too, you know!!