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Truss rod adjustment issues

Discussion in 'Hardware, Setup & Repair [BG]' started by pushbuttonfour, Aug 11, 2013.

  1. pushbuttonfour


    Dec 20, 2012
    Sorry if this question has been asked before (I dont think it has) but I tried adjusting my truss rod recently and wasn't able to do it. I stuck the Allen wrench in the hole by the top of the neck of my bass (Fender P bass), but when I turned the Allen wrench, nothing changed. I tried several different sizes of Allen wrenches, but I couldn't feel any resistance while turning any of them. Is it possible that the hole has been stripped and the truss rod is now impossible to adjust? I got my bass used so I suppose that might be the case. But it's more likely that I'm just doing something wrong. Can someone explain exactly how to adjust the truss rod? I would be very grateful.
  2. pushbuttonfour


    Dec 20, 2012
    Here's a picture of the hole just so everyone knows what I'm talking about. As you might have guessed, I've never adjusted the truss rod before, and I'm inexperienced at making adjustments to the bass in general.

    Attached Files:

  3. soflbass


    Mar 2, 2013
    S Florida
    Usually a fender uses a 3/16" Allen key. Squier uses a different size. What brand/year and how bout some pics of the action at the 8th fret and near the heel. Have you done any measurement of relief and action height? See setup guides pinned to the setup forum.
  4. Looks as though the TR nut is goners.

    Do you see a threaded stud when you shine a flashlight in there?
  5. Lownote38


    Aug 8, 2013
    Nashville, TN
    You'll know when the hex key wrench is seated correctly, but the trussrod nut might be so loose that turning it a bit doesn't put any tension on the neck at all. Also, even though the short end of the hex key will usually reach far enough in there, try the long end and see if you can get it to sit in the truss rod nut that way. First and foremost, shine a flashlight in there and see what's going on. Is the nut there? If so, does it look all chewed up, or rounded out?
  6. Squier uses 4mm.

    Use a ball end hex key. You don't have to be straight-on with it then as it'll bite even if it's not all the way in - not having a good bite is probably the #2 cause of stripped truss rod nuts. #1 is using a key that is close, but not quite, the right size.

    I vote flashlight as well. That's 3 of us so now you're going to have to do it ;P

    Remember: righty-tighty lefty-loosey. Tightening adds backbow to counter the string tension, loosening removes backbow and lets the strings pull the neck forward. If the neck weren't under so much stress I'd say to always tighten (like when tuning), but it is, so letting it out isn't so bad. Either way, make SMALL adjustments over time. Don't turn it more than about a quarter turn at once before giving it a day or so to settle.