Proper Hub Oil Level

Discussion in 'Trucks [ Eighteen Wheelers ]' started by 98T800NY, Mar 1, 2024.

  1. 98T800NY

    98T800NY Bobtail Member

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    Feb 14, 2024
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    Hey guys I'm back with another Newbie question haha.
    I was looking at my trailer and to me it looks like at least 2 of the 4 hubs are low on oil. I've included pictures of each hub in the post.
    I'm seeing a lot of conflicting information on the internet about what it should be filled to. Some say the fill line, others say fill it to the point where if you stick your finger in, your finger tip gets wet. Lastly some say fill it right up the the plug hole like you would if you were filling a differential.
    The trailer was an auction buy so I don't know the history. I don't see any seals leaking and inside the wheels by the drums look dry, no signs of oil leaks. I have a old 1983 Penski Dry Bulk trailer.
    Thanks for any insight, this forum has been great.
    hub 3.jpg hub 4 (1).jpg hub 1.jpg hub 2.jpg
     
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  3. Coolbreezin

    Coolbreezin Medium Load Member

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    As an O/O with a 1991 truck with the same hubs, Id flush extremely well and fill it to the recommended level on the hub cover.
     
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  4. skallagrime

    skallagrime Road Train Member

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    As a preventatitve, coolbreezin is correct, but the only one im extremely leery of is hub 3, the rest look like oil, 3 looks like dirt mixed with water
     
  5. 98T800NY

    98T800NY Bobtail Member

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    When filling to to "full" line would you consider it properly filled in Hub 3 or is Hub 1 at a better full level?
    Hub 3 almost looks like it is above the full line and overfilled.
    I know the sight glasses are hard to see, sorry about that.
     
  6. skallagrime

    skallagrime Road Train Member

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    Between add and full is the correct level, obviously closer to full than the add line.
    3 is definitely overfull, but see above post
     
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  7. 98T800NY

    98T800NY Bobtail Member

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    I just went out and dipped my finger in hub 3. It feels like good gear oil. I is a lot cleaner/newer looking gear oil than is in any of my oil hubs. Also is my newest looking sight glass so it makes me think the previous owner may have changed that one out not long ago or done some service and accidentally over filled it. Should I run it at that level or try to bring it down a little? A flush and fill would allow me to adjust the level.......
     
  8. skallagrime

    skallagrime Road Train Member

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    Fair enough
    Reduce to correct level should be good enough, there SHOULD be an allen key style plug in the hub itself if you can break that loose to drain, should be pretty easy, IF you can break it loose that is...
     
  9. Arctic_fox

    Arctic_fox Experienced mx13 execrator

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    Id flush fill all of them anyway. Its not that espensive, lets you get new gaskets on, and ensures you have fresh gear oil in there. Also will show if there is any metal or anything else of concern in there or any damage you may not be able to see with the hub on. Also lets you set a maintaince record for that item.
     
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  10. skallagrime

    skallagrime Road Train Member

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    For the record, this is still the smart thing to do
     
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  11. FLHT

    FLHT Road Train Member

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    The clear plastic lens are cheap and easy to replace.
    I would also put new plugs in Cheap too.
    The plugs have a small hole in center to let pressure from heat out.
     
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