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Is this a Hub Problem?
Yesterday we made an uneventful run from Lake Toxaway, NC to Hilton Head Island. I did do a couple of walk-arounds en route, and did not see anything amiss. It was raining, so I might have missed it.
Today my right tag showed evidence of an oil leak, enought to have a small drip onto the tire. I removed the hib cover expecting a problem. What I found was the little red cap stuck in a smear of oil on the interior of the hub cover. Surprisingly, the oil level is still just below the MAX line. (I guess oil is like blood, a little can look like a lot!).
So, my questions are: Does this cap just fall out, or does some situation force it out? Do I just clean up, put the cap in and go on?
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4 Replies
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John,
What comes to mind is has it been recently serviced and if so, could it have been over filled or just not evenly pushed back into place?
The bigger ones like my XL have a really tiny vent hole in the cap to relieve pressure and sometimes that hole needs cleaned out with a needle so it can vent. Maybe someone here with an XLII has knowledge of the smaller cap, but I would think it would also have a vent hole.
I would also assure the wheel is not getting hot causing pressure due to a dragging brake caliper. Once you get it cleaned up and put back together, check the wheel temps after about an hour of driving on each side to see if they’re consistant.
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Thanks Tom. It has probaply been 1500 miles since service at Prevost Nashville, and this oil positively started on the last leg og this trip. I will check for a small vent hole tomorrow.
I did notice that coming from the relative high altitude in the mountains to sea level here at HHI some partially empty plastic bottles had “crushed in” a little. So it stands to reason the atmospheric pressure change could pop a cap off going up the mountain if the vent was plugged.
I will certainly use my IR thermometer on the next leg (in about a week).
Anybody else? Jon?
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Tom is right about there being a small hole in the red cap, in the center, about the size of a small needle. It is there to vent excess pressure from the expansion of the fluid as it heats up while driving and pushes against the air in the hub. Overfilling the hubs contributes.
When you push the cap back it should be a tight fit, If it is loose the cap or maybe even the whole housing needs to be replaced.
This is not the first time I have seen this. Another PC member pulled into a rally in an H3 and the wheel was also oil covered and the cap was also sitting in the hub cap. That cap did not fit tight so temporarily we added a couple of wraps of electrical tape around the cap so it had to be snapped in place until a new cap could be found. Not the same cause, but I had a separation of the clear plastic and the metal housing on my hub cover that allowed the hub grease to leak. In every case as you say a small amount of grease was lost, but it looked like much more was gone.
I think I have a spare hub cover and gasket if you need one, John
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There is enough oil in the hub if maintained at .. min level. When the oil heats up it will be inbetween the min and max level. Most techs only fill to just above the min level. The high level probably has caused the cap to push out from the ridge it fits into.
As long as the gear oil is not milky looking from water getting inside the hub you should be fine. A small suction gun can remove enough oil to arrive a the preferred level just above the min. Without a suction gun use a small clear plastic hose inserted into the hub and draw the excess into the hose.
Good idea to check the other side also for overfill of hub oil.
The red cap in the photo looks OK
AL
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