Primary Filter half full

Discussion in 'Trucks [ Eighteen Wheelers ]' started by shoesw9, Jan 30, 2011.

  1. shoesw9

    shoesw9 Bobtail Member

    11
    0
    Apr 10, 2009
    pinckard,al
    0
    Have a W9 with MBN, coming home the other day from Nashville headed south on 65 it wasn't pulling like normal. I stopped at the Tennesse'n and checked my primary filer for water, it was half full of fuel,no water. It was down about 5psi of boost and idled rough, I was ready to get home so I flipped the return bypass open so some of the fuel would go back to the transfer pump and it run as normal. So the question is where do I start trouble shooting? :biggrin_2552:
     
  2. Truckers Report Jobs

    Trucking Jobs in 30 seconds

    Every month 400 people find a job with the help of TruckersReport.

  3. kwforage

    kwforage Road Train Member

    1,047
    472
    Jun 3, 2007
    Wisconsin
    0
    The same thing happened to me when my secondary filter had a pinhole leak. The primary would be half full everytime I pulled it. I would look for a air leak somewhere between the tank and filter.
     
    rollin coal and shoesw9 Thank this.
  4. turnanburn

    turnanburn Medium Load Member

    628
    270
    Jan 25, 2011
    central Vermont
    0
    since it's real hard to find a suction side leak, we've put real low air pressure into the tank to push fuel out through the lines--then the leaks show. Works on the old Cummins anyways.
     
    shoesw9 Thanks this.
  5. CAT FLASH

    CAT FLASH Bobtail Member

    32
    16
    Jan 10, 2011
    Alabama
    0
    Check your stand pipes in your tanks...I've seen these fatigue and a hairline crack would develop. Also I'm sure it would be leaking and you would already notice it but I've seen the restrictor just below the air compressor in the bypass line get a small hole in it from vibration.
     
    shoesw9 Thanks this.
  6. shoesw9

    shoesw9 Bobtail Member

    11
    0
    Apr 10, 2009
    pinckard,al
    0
    Cat Flash what are you calling the restictor?
     
  7. CAT FLASH

    CAT FLASH Bobtail Member

    32
    16
    Jan 10, 2011
    Alabama
    0
    There is a fuel restrictor inline in the fuel return line going back to your transfer pump. It's secured just below the air compressor and it's hard to see since it's secured by a rubber coated band and a bolt.
     
  8. shoesw9

    shoesw9 Bobtail Member

    11
    0
    Apr 10, 2009
    pinckard,al
    0
    Ok, I spent 2 hrs looking this afternoon for cracks and leaks. I will look harder on the return line to the transfer pump, It is a little chafed from rubbing on the block insallation.
     
  9. CAT FLASH

    CAT FLASH Bobtail Member

    32
    16
    Jan 10, 2011
    Alabama
    0
    Sounds good. Where's Pinckard at? Never heard of that place...If you turned your bypass valve back on more than likely you will see some fuel leakage somewhere while it's running.
     
  10. droy

    droy Heavy Load Member

    828
    159
    Jun 11, 2008
    Iowa, LA
    0
    I'm thinking you are referring to that brass gizmo that resembles an automotive inline fuel filter. The one on my MBN started leaking recently, the rubber coated steel strap wore through the brass at the end, causing fuel pressure to push the o-ring out of place, small fuel spray eventually wetting all the way to the drive axles, but I don't remember it causing my truck to miss, or not keep the filters full. Perhaps my leak wasn't bad enough, it started in early evening, and after driving most of the night, I exited the truck to see the mess. :biggrin_2555:
     
  11. Sodapop

    Sodapop Light Load Member

    91
    7
    Mar 19, 2010
    Blytheville,Ar
    0
    are you suppose to have the cut off on or off coming from the return line going to the transfer pump..my filter is staying no more than half full..and i have changed check valves,filter bases used differnt filters and even changed the primer pump on the secondary base
     
  • Truckers Report Jobs

    Trucking Jobs in 30 seconds

    Every month 400 people find a job with the help of TruckersReport.