READ THIS IF YOU’RE CHANGING YOUR OWN BEARINGS…
Firstly, when replacing bearings, replace the whole lot, not just the obvious crook bearing or seal. Do both sides as well, even though only one side might be noisy. Before tightening off the axle nut, make certain that you cover the whole assembly with good quality bearing grease, and in the case of boat trailers, quality marine grade bearing grease.
Finally, because the bearings are tapered, you must put a gentle pre-load on them. This means that the whole bearing assembly must be slightly compressed. Experienced mechanics can do this by hand, but when in doubt use a tension wrench to tighten the wheel nut. Don’t forget to fit the split (cotter) pin. Which bearing do you have? Ford or Holden.
The easiest way to find out is to check the inner diameter of the front (small) bearing. The Ford bearing is about 22mm, the Holden about 19mm.
You need to have this information before you get a spare!