Front hubs and rear tags MC8

rcbeam · August 07, 2011, 03:34:26 PM

My book says "Front and rear trailing wheel hubs use oil lubrication, SAE 30. Level should be visible in the sight gauge level mark... if not, add. I pulled out the rubber PLUG and do not see a sight gauge level mark"... the two fronts had a quantity of oil there... but not sure how high up it should be.

Further my book says "oil should be added through the composition snap plug at the center of the hub cap". Is the rubber plug I pried out the composition snap plug?

Now, the curb tag had oil but not as clean as the front but more oil as it ran out when I pulled the plug out. The street tag had no oil but what looked and smelled like dark grease. The wheel lug nuts had an oily film on them and the wheel did also... not a lot, but not dry like the other wheels so I guess I have an issue with the street tag.

Could it be that a different bearing was used as replacement on the street tag and it used grease instead? Should I just take it all apart, clean it, and put back with oil? I'm lost here. I hope to make a trip in October to have Fred Hobe do some work on the bus and I don't want any surprises on the road. Figured I better look at this stuff now.

What say you guys on the oil hubs?

edroelle · August 07, 2011, 04:02:59 PM

Luke recommends that for coach conversions with limited use, that wheel bearing be lubricated with grease rather than oil. I have changed a couple of mine from oil to grease when I work in that area of the bus. Your axle may have already been changed.

Ed Roelle
Flint, MI

busnut104 · August 07, 2011, 04:50:37 PM

I changed mine from grease to oil, I use the Luke us Hub oil and sealer, have not had a problem. I feel that you get better lub with the oil.

JackConrad · August 08, 2011, 05:03:14 AM

If the hub covers have a removeable plug in the center of them,you have the oil type hub covers. However, someone could have removed the covers, removed the bearings, packed them in grease and re-installed everything using those covers. That is what we found on our bus when we did our 1st PM after getting the bus home.
The "full mark" is a thin line molded into the cover (may be difficult to see). When full of oil, the oil is about 1/4" below the bottom of the opening the plug fits into. There is also a small pinhole in the center of the plug. This opening allows air to escape as the hub warms up when driven. If plugged, the heat build-up can force oil past the seal. Jack

Ralph7 · August 08, 2011, 09:38:53 AM

I replaced the wheel bearings in front and greased them. The drives were replaced and packed with greased knowing that the diff. oil would get there.
The tags were full of fresh oil and looked good, but 4,000mi. later the left tag let go, well the bus had set for several years and the tag bearings were the only ones with signs of rust on rollers and races, so they were all changed, and greased.
If you do not turn those wheels often the lube drains off, and rust starts.

Just Dallas · August 08, 2011, 10:46:20 AM

I'm fond of the Stemco hub covers. There are two lines, one is 'add' one is 'full'. If you go over those, the oil will blow out the hole in the plug, covering everything behind and around it with oil.

In the picture I'll try to post, you'll see where the lines are. I try to fill to a space centered in between the lines to deal with humidity, temp and altitude.

If you try to fill the hub to the top of the line you'll end up blowing all the extra out, and if there isn't enough of a relief hole in the rubber cover, it will blow out the back of the seal.

http://www.maraindustrial.com/cart/images/detailed/KOdde15zOIMG_0890.JPG

rcbeam · August 08, 2011, 02:08:15 PM

Since my post I did a search here and also on BNO... it seems more posts on BNO on that search recommended changing to grease and the opposite for on this board. Dallas, I like the way the Stemco hub covers look... real snazzy. However, I think I will put it on my list to change both tags to grease and have the seals changed (doesn't it take a special tool to change the seals) and then leave the fronts until later. I have no idea how quickly the oil drains down and the bearings start to rust. I hope to drive the bus every two weeks in the winter, but if it's like last winter that may be hard to do. Sometimes all you can do is the best you can.