Originally Posted by acadianbob
If you have the modern hubs with zerks, they work fine and I don't see the need to pull the bearings every year. (Bearing Buddies are another story as OC mentions). I've got 30K miles on my trailer. I "zerk lube" the hubs twice a year. After 5 years and 25K, I had the bearings examined. They were perfect. Repacked them, reinstalled them. Will be "zerking" for another 5 years.
At the factory, they do not fill the hubs with grease (just the bearings) when they install them.
Some rules on Ultra-lube axles:
1) ALWAYS use the correct spec grease - too thin and the grease will run out when hot; too thick and you will not be able to get a good flow using a hand grease gun.
2) ALWAYS use a hand grease gun. If you need more pressure than that or the hub won't take grease, you have a clogged Zerk; clean or replace. Air pressure grease guns will blow out your rear seal because the grease is pushing against the bearings and the full hub; the rear seal is will pop before the pressure can move the remaining grease out of the way.
3) The first time you fill an empty (or recently repacked/inspected hub), it will take a lot of grease. Don't worry; it will come out the front like it is supposed to.
4) Remove the entire cap (not just the rubber) for a new fill or bearing flush. There will be a LOT of dirty grease coming out. Never stick your finger in the bearing cap to scoop out the grease (sharp edge; don't ask how I know).
5) Put a squirt in before every trip and every few thousand miles. Wait till you see the blackened grease be replaced by clean grease (will retain the color of fresh). Every so often there will be a LOT of black grease as the rear bearing dirty grease gets pushed through the front. Just keep going until it is clean grease.
I repack every three years or when the brakes need to be changed.
At the rally, I had new self adjusting brake assemblies installed and the technician said my bearings still looked like new after over 25,000 miles.