Front Hub / Tag Hub Information

As the plug ages, it will get harder. When this happens the plug can leak around the outer edges. They also are easy to turn/spin by hand. A new plug is not as easy to turn. If you are seeing oil streaking only on the front of the wheel, then new plugs bay be in order.

Stemco Hub Cap Rubber Cap Plug 1-1/8“ - 359-5990

Also of importance is that the Stemco red rubber plug covers have a center vent hole that needs to be periodically cleared with a straightened paper clip. A plugged hole can put pressure on seals.

Parked on a level surface (side to side), if you are not then one side will look over full and the other side low. The oil level should be at the inner ring (below the plug), that is the full mark. Don't overfill or the oil will get slung out, don't under fill as there is not much oil protecting the bearings.

The hubs use 85W-140 gear oil, you can find it anywhere including Walmart. Just remove your front hub caps / “top hats” (pull off the decorative lug covers and the rest will come right off). Once done you will see a red cap, its a rubber plug and will pull right out. Add in the gear oil until you are at the full line and put the plug back in.

If you are not replacing seals and want to change over to a synthetic gear oil, just use a transmission pump to pump out what you can from the fill plug. Get what you can and then let it sit for short while, this allows more oil will drain out of the bearings, pump that out as well. Now fill up to the fill line, again let it sit and top off as needed.

You will have effectively changed >80% of the fluid over to synthetic without breaking down the wheel. Do it again if you want an even higher percentage.

Recheck the levels in a couple of days as the oil has to seep through the outer and inner bearings to equalize the level.

If you find that your hubs need oil, most likely you will need new seals which are on the inside part of the wheel hub. If you have oil inside the wheel and on the disc brake rotor, you need to have the seal replaced (a job for the Pro's only).

A bad seal may not have any evidence of seal leakage whatsoever on the outside of the wheel, but the inside of the wheel and the rotor can be well doused with leaking hub oil.

If you find this and are not close to a repair shop and can't do the repair yourself, you can try the following limp along method. Remove as much oil as possible from the hub and then added Lucas Hub Oil back to the full mark. Recheck in a short while to allow the oil to seep through the outer and inner bearings to equalize the level. The Lucas oil is a proprietary blend of synthetics for extreme duty applications, it is a very high weight oil. Professional truck fleets use it whenever they have evidence of a seal going bad.

Be sure to cleaned the inner part of the wheel and the disc brake as thoroughly as you can of any old oil that leaked out. Drive a short distance and then checked for leakage on the inside of the wheel and overall oil leakage. If it looks good continue on for another short distance and recheck. Do this frequently during the rest of the trip.

The repair kit contains a new seal and a ring upon which the seal seats. The seal is installed in the hub and rotates. The ring fits on the axle with a tight fit so that it does not rotate. Unless you know that it is there one would think the ring is part of the axle. A pry bar type tool is needed to remove the old ring and the new one can be installed by using a brass mallet and/or the old ring to gently drive it in place.