3406E Jake Housing mounts torque specs

Discussion in 'Trucks [ Eighteen Wheelers ]' started by Straight Diesel, Jul 16, 2025 at 8:00 PM.

  1. Straight Diesel

    Straight Diesel Bobtail Member

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    Jun 14, 2025
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    Hello friends,
    First time poster here. Was wondering if anybody can confirm if I have these toque specs correct. I am doing some fuel injector and electrical diagnostics and just put it all back together under the valve covers. My Jake housing on the 3406E (6TS) is 340A. I have 4 mounting bolts and 2 rear nuts (pictured below). I know these all have different names, but to avoid confusion I am mentioning placement.

    I believe they all torque down to 80 ft lbs, more specifically 50 ft lbs - 1/4 turn - 80 ft lbs

    And the valve covers bolts along with valve cover base 13 ft lbs.

    Also notice the one mounting bolt is a different diameter? This is the only model I’ve seen this on, anyone know what that’s about and if it’s torqued the same? I would think so. I’ve circled all mounts, the orange and red is the smaller diameter bolt. I believe it’s 5 or 7/16 off the top of my head and the rest are 3/4” and the nuts are of course larger.

    Thank you anyone that has any input!
     

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  3. 062

    062 Road Train Member

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  4. W923

    W923 Road Train Member

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    Feb 28, 2022
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    I don’t know the torque off the top of my head but just because 50 ftlb+1/4 turns makes 80 ftlb one time or even several times it is not safe to assume you can use 80 ftlb interchangeably. I can write a long post about why but for the sake of time I won’t
    I am almost certain your cover bolts at 13 is correct though.
    Is that bolt actually a different diameter at the thread or just for some reason have a 12pt head
     
  5. Straight Diesel

    Straight Diesel Bobtail Member

    5
    4
    Jun 14, 2025
    0
    The different diameter is just the 12point head and fits approximately a 13mm socket. It’s the same under each cover so it doesn’t look to be a replacement of any sort.

    I called a CAT shop and that’s where I got the 80 ft lbs from and they sent me a snap shot of the quick guide which had me confused for a moment. Anyway I tightened all down to 80 and honestly when taking them off they felt way tighter.

    And after all that I must have messed up setting the housing back in, looked to all be lined up, but the engine is turning but won’t fire. So now I have to start over on that or do an overhead.

    Never done any of this before, but it seemed simple enough. I took my time.
     
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