WHAT IS E-Z LUBE®?
The E-Z Lube® system consists of axle spindles
that have been specially drilled and assembled
with grease fittings. When grease is pumped into the fitting, it is channeled to the inner bearing, then to the outer bearing, and eventually back out the grease cap hole for a complete bearing repack. The protection and maintenance features of the E-Z Lube® system make it ideal for most towable axles. E-Z Lube® is designed to allow for immersion in water.
From the link to the website
Thanks,Dog Folks
I wondered myself how one kept from blowing the seal.