The term 'Water Proof' is relevant, so I'm not going to say that this page will make your hubs 100% water proof, but it's sure saved me a BUNCH of bearing repacking every time I splash through some water when off roading!

Helping your hubs be more water proof is simple, but will take a bit of work on your part.

"Any air space in the hubs is bad"..
Some people will disagree with this statement, but the actual physics of things pretty well proves it.

The reason being, air expands and contacts, and every time it does, it brings in moisture to your bearings.
As soon as the drawn in air from a cooling hub equalizes temperature, it sheds it's moisture in the hub, so you don't even have to move the vehicle to get moisture in the hubs!

A hot hub splashed off in cold water while off roading will 'Suck' a 'Breath' in when it rapidly cools, bringing in water like crazy!
Where grease is, air can't be, and where air ISN'T, it can't suck in water...

I have a little 'Trick' I use when greasing the 'Axle thru Spindle' air gap...

Most guys just goop the spindle full of grease, and they are correct for doing so!
Anywhere grease IS, air and moisture CAN NOT be!

I do things a little differently.... (as you can tell by the rest of this web site!)
I drill a small hole in the spindle while it's cleaned up and before new parts are installed, and use a 'Grease Needle' to fill the spindle after it's on the knuckle with the axle sticking out of it...

Drill right behind the inside bearing surface, and keep the hole small enough it WILL interfere with the taper on the needle, so you can get a reasonable seal just by pushing the needle into the hole.

Notice I index the hole to align with the slot for the locking washers?
This makes it easier to find when everything is greasy later on!
Most of us index that groove up or forward on the knuckle, so that makes it easier to get to.

Grease needles come in a few different sized, but the cheapest way to get one for this particular application is from a farm supply store.
The one I use is made for lubrication of a chain saw blade roller tip, and it's not the hypodermic type used for CJ joint boots, ect.

Don't forget to Pre-lube the spindle needle bearings and seals before you mate the spindle with the knuckle.
You don't want 'Dry Starts' here!

Don't forget to 'Never-Seize' the back side of the spindle where it mates with the steering knuckle!

Tech Fine Point!
DO NOT USE NEVER-SEIZE OR LUBRICANT on the knuckle to spindle threaded studs!

These use 'Crimp' or 'Crush' type nuts, and you shouldn't use lube with them.
Always replace these nuts, (3/8" SAE or 'Fine Thread).
Crimp nuts are lock nuts, and they are SINGLE USE.
New nuts are cheap, and you can get them at any NAPA.

Don't use lock washers under them. The nut IS the lock.
This is one of the few exceptions to the 'Never-Seize' or 'Lock-Tite' rule on a Jeep.
Torque to 35 to 40 lb.ft. and smile since you didn't get greasy or covered with never-seize or lock-tite with these nuts! That will be a rare thing with your jeep!

The same principal applies to hub as applies to the spindle.
Where grease is, Water can't be!

I drill and install a grease 'Zerk' in the hub,
(A grease 'Zerk' is the nipple/valve that the grease gun connects to. Zerk is a brand name that stuck)

And it's installed so its protected from the wheel removal & install, and so it's angled to where I can pump grease directly into the chamber between the wheel bearings, eliminating the air gap in the hub.
The angle of the hole for the grease is a little severe, to make sure you come out inside of the outer bearing, but it's very do-able with a hand drill.

Notice in this first picture there is a 'Void' inside the hub behind the outer race?
This is the 'Knock Out Notch' for the races when you service the hub.
I usually try and drill into these if I can, but sometimes on some hubs they line up with the studs, and you cant get the Zerk too close to the stud...

Since grease out of a grease gun is a very tiny stream, I pilot drill with a much smaller bit that I'm going to use for mounting the Zerk on the outside of the hub.
1/8" pilot hole is PLENTY for this stream of grease!

For me, this is a good thing, the less material removed, the stronger the hub will remain...

Although I've NEVER heard or seen anyone saying the split a hub out!

I can actually flush (I won't say 'repack') my wheel bearings with fresh grease with out having to remove the bearings from the hub this way.
Just be careful when changing the wheels on the front, and try to keep the Zerk pointing 'Down' when you change wheels, so the wheel edge doesn't rake or sit on the Zerk when you are installing or removing.

Painting a small strip on the hub that lines up with the Zerk is a good way to remind you, and keep track of, the Zerk.
It's also something that a 'Real Jeeper' will ask questions about, and the average 'Joe' won't notice...

Mall Pounders and Wally-World parking curb heroes won't like the paint stripe, but they aren't real off roaders anyway, so the point is moot for them.

When you are ready to put the hub on the spindle,
DON'T FORGET to Lube the hub inner seal!
Again, this keeps 'Dry' starts from ruining the seal.

If you don't have a bunch of drills and taps, then there is an easier way to do this...
The drill you need for the spindle and pilot hole in the hub is 1/8" or there abouts.
A little smaller is OK if you can't find a 1/8" drill bit handy.

To mount the Zerk fitting, you only have to drill in on the pilot hole about 1/4" deep, (or slightly more depending on the angle of your pilot hole) with a #5 drill.

This gadget, is a Zerk wrench.
It has ends for installing the small size Zerk fittings, both straight and angled,
An 'Easy Out' for removing broken off fittings,
And a tap the correct size for cleaning out threads or for threading holes for new fittings.
Very handy thing to have if you actually grease your jeep the way it's supposed to be done.

The common small grease Zerks are 1/4"x 26 TPI NF,
(TPI: Threads Per Inch, NF: National Fine)
And that is NOT your average fine thread...

1/8" drill.
#5 drill.
2 small Zerk fittings.
1/4" X 26 NF tap.
Cutting oil.
Hand drill.
Fitting wrench for small fittings.
Paint marker.