View Full Version : Oil Bath Hub Manufacturer Specifications

04-14-2008, 12:42 PM
Having seen several posts regarding recommended oil and fill guidelines, I found this document which is from one of the manufacturers of hubs, UFP.


UFP specifies 50W engine oil and recommends filling completely and not leaving any air at the top since air expands and contracts more than oil. Anyway, just wanted to pass it on.

Edit: This applies to UFP hubs only. Mine is a '02 and the axle has UFP stamped on the torsion arm. If you read on, it appears UFP was only used for a short time, and MC switched to Reliable.

04-14-2008, 01:09 PM
According to Mastercraft Parts/CS, UFP only supplied a oil bath wheel bearing system to MC for approx. 1 year and UFP may have recommend 50wt oil, but since then the supplier to MC has been Reliable and you need to follow their recommendations per your owners manual, if you have a Reliable system.

04-14-2008, 02:10 PM
I should have specified, mine is an '02, so the picture at least looks like mine. I cannot find a specific '02 manual, but they look exactly like the hubs depicted in the link below, which look just like the UFP hubs pictured in the UFP manual. Do the Reliable hubs look the same? I can't find a website for Reliable to see a picture.


And here I thought I was being helpful....

04-14-2008, 02:43 PM
IIRC, the Reliable hubs have an oval with the word 'reliable' molded into the clear observation cap on the hub.

04-14-2008, 02:45 PM
OK, upon pulling mine apart, I see that my axle is a UFP. In re-reading p-hat's post it looks like his are in fact different. I am ASSUMING that his are the Reliable hubs--I know at least that they are not UFP. So, I am guessing this is why there are several different recommendations floating around about which oil to use. It appears the UFP specifies 50W and Reliable specifies 80-90W. Now, the $1000 question, is one better than the other? I suppose I will follow the recommendation of my hubs and go with the 50W.

04-14-2008, 10:01 PM
Once the 50W vs 80-90W question os settled, how about the fill recommendation. UFP clearly said filled means no air. How about a recommendation for Reliable. I checked the MC Trailer Manual, but it's not specific. Mine is an '06, and the hubs have always had about the top 1/4 of air.

04-15-2008, 12:09 AM
FWIW - In the reliable hubs on mine, I've run both the 50W motor oil and 80-90W gear oil with no difference. Filled up the hub about 3/4 full, but my axle is not pressurized with the spring set up like the one you posted. I can understand why they'd maybe want you to fill that one up completely to avoid water intrusion.

04-19-2008, 03:38 PM
The logic makes sense to me-a gas (air) will expand much more when heated than a liquid causing a pressure buildup in the hubs, potentially forcing out air or liquid, causing a vaccuum when it cools--i.e. when the hubs hit the water. But, that is just theorizing, would be nice to know what Reliable explicitly recommends.