Running Wet Hubs Up Front
(and some Defender and Range Rover Classic)
Recently, I noticed a psychedelic pattern of gear oil splattered upon my front wheels of my D1. I just rebuilt the swivel balls, with all new seals, and it wasn’t leaking out of the outer swivel seal (thankfully). Instead, it seems that I had two issues combining: the gasket on my drive flange had failed, and one or more of the seals meant to keep my gear oil in my axle and swivels separate from the grease in my hubs failed.
I decided to take this opportunity to return my truck to basics. Up until the mid-1990s, all Land Rovers had run what is called “wet hubs” since 1948. There were no seals to restrain oil between the drive flange and the differential. This would require more gear oil, but gave the benefit of the superior lubrication of gear oil in the hubs.
The issue with this is that as seals or gaskets failed, there was more opportunity for gear oil to evacuate itself from the various components of the front end. As Land Rover entered the North American market as more of a luxury brand, this dripping did not go well with flagstone driveways and pristine garage floors. Thus, Land Rover installed several seals that would separate the hub from the axle and swivel assembly. The swivel assembly was filled with a “one shot” grease, and the wheel bearings were lubricated only by wheel bearing grease in an otherwise-dry hub. As these various seals fail, gear oil from the differential slips down the axle tube and begins to contaminate the hubs and swivel assemblies. Well, “contaminate” — this is a good thing, as the gear oil is a better lubricant than grease alone.
It’s become popular among the more handy coiler Land Rover ownership to convert to “wet hubs” by removing some of these seals, and running gear oil from drive flange to drive flange.
To do this requires removing several of the seals, and tearing down the axle to the level of the swivel balls. It’s not a super-quick operation, but it will pay off.
One thing you will need to do is replace your hub seals that keep the inner wheel bearings in. You’ll need part number RTC3511, which has a double lip to keep the oil in better. This is an earlier Defender/Land Rover part, and honestly you should be using them whether or not your hubs are wet if you ever have the hub apart.
Another thing you’ll need to make sure of is that your drive flanges are very well sealed on the hubs. A poor gasket, a busted rubber dust cap, or severely worn splines and you have great potential for a leak, which will coat your wheel with gear oil. These, the inner hub seals, and the swivel ball seals are now the only things between potential ingress of contaminants and your entire front axle. This may be an opportunity to upgrade your front drive flanges, to one of the offerings from Terrafirma or Ashcroft. If your truck has seen a lot of adventure and the splines are slightly worn against the CV stubs, it also could remove some of the slack in your stacking of tolerances.