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Truss rod stuck / broken?

GregBEL

GregBEL

May 25, 2013
41
0
Belgium
#1
Hi all,

Recently I picked up an old bass as a project (see my thread if you want to help me identify it http://www.talkbass.com/threads/diana-bass-origin.1092465/). The neck of the bass itself is in decent condition, however, I seem to have some troubles with the truss rod. The truss rod nut is at the heel as you can see in the picture below. I haven't seen a nut like this before. My initial thought was 'ok, I'll insert a long rod through the holes and that will give me enough torque to do necessary changes'. It doesn't move, at all... I tried on numerous occasions, after removing all the strings, after completely removing the neck, it won't turn in either direction.

After some reading here on tb I came across some helpfull ideas such as adding some penetrating oil (Kroil, PB blaster) overnight, or slightly bending the neck to relief some tension and then turn the nut. There's another thing I noticed that I want to mention before doing anything like that: when hitting the open E string something resonates (vibrations/noise)... At first I suspected the tuning pegs, but I'm afraid the noise seems to be coming from inside the neck, so that should be the truss rod I guess. Would this be a sign that the truss rod is broken? What would you guys recommend to troubleshoot this problem?

One obvious reason I would like to fix this issue is because I need to adjust the truss rod to set up the bass properly. Also, because something resonates, there's a significant drop in volume and sustain on the open E string which is really not desired.

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Many thanks!
Greg
 
#2
Well, it should turn in some direction and you've used the usual penetrating agents. Try heating the truss rod nut with a big mambo soldering iron and cranking on it while the SOB is still hot. Works on lug nuts when everything else fails.

Riis
 
#4
Try the PB Blaster first, giving it time to penetrate. I would try pressure a little each way next, just to get it to loosen- if it gets pretty stiff, go back the other way a little before continuing.
The 'stuck' nut doesn't really have anything to do with whether it may be broken or not- if it's stuck, it's probably not broken.
The vibration you get may be because the trussrod is not tensioned against the string tension, and all may be just fine when the nut is freed
and the trussrod can counter the strings like it should.
 
#5
If you turn it very slightly in either direction, does it seem springy? In other words does it turn a tiny bit,
and then want to spring back to it's original position?
If so, the rod isn't broken; the nut is frozen on the rod threads. Another possibility in this case, is that the
nut has reached the end of travel on the rod threads and has tightened onto the rod. (like turning a nut onto
a partially threaded bolt all the way to the ends of the threads and then tightening it against the end of the
threading)


If the nut will not move at all with reasonable force, It could be that the rod is under excessive tension.
A truss rod can end up in this state by a large amount of tightening, Therefore it is usually safe to turn
the nut counterclockwise a very tiny amount, to break it free. When it is that tight however, it is hard
to judge whether or not the nut is turning on the rod, or the whole rod is twisting.

If you can see the end of the rod through the hole in the nut, try marking it somehow so that you can see
if the rod itself turned. If you get the nut to move, check that the rod has not turned.

-
 
#6
Penetrating oil and heat. Loosen and remove it to inspect and lube the threads. If you feel the "springy" stop turning, hold it there and tap the nut with a hammer. Apply rotation to the other direction and repeat. No luck? More oil and another day and repeat. Gentle patient determination will get that sucker off.
 
#8
megafiddle said:
If you turn it very slightly in either direction, does it seem springy? In other words does it turn a tiny bit,
and then want to spring back to it's original position?
Click to expand...

At one point I thought I had it moving, but then I realized it was just the metal rod I used for turning that was bending... So no, it's not springy it's really completely stuck at this moment.

I will go with the penetrating oil and let it sit overnight. Then with or without heating I will try again the next day. Would you guys also recommend WD40 to do the job? I'm not sure where to find PB Blaster here (Belgium). I will go to the hardware store to take a look at others though.

apostrophe said:
Out of curiosity, that's a Hondo 2, isn't it? My first bass was exactly the same- a P-copy with burst, maple and the same old pickup. My dad bought it for me around '82 from Sam Ash out on Long Island.
Click to expand...

Actually mine is labelled 'Diana' but yes - similar to your Hondo it's a Japanese made P-bass-ish copy. See the link to the thread in my first post for some more pictures if you're interested.

Thanks!
 
#9
WD40 is better than nothing just DONT spray it in there. You don't want to soak the wood with it because that MAY cause the wood to soften. Drip a couple of small drops into the hole in the nut, holding the neck vertical, with a toothpick or similar.
 
#10
WD 40 is not a penetrating oil nor is it designed to function in this manner. Any benefit that comes from it's use in this particular scenario is merely coincidental.

Go to the hardware store and ask for penetrating oil. In the USA, 3 in 1 is a popular brand. There are many others.

Be careful to restrict the flow so as to not get oil on the wood. A few drops is all you will need. Keep it off the wood.
 
#13
Thanks for the heads up. Indeed, WD40 is not ment to do these jobs.

My local hardware store had 2 different brands, both with graphite additifs for lasting lubrification. One of them is Griffon IMAL, also contains nafta and light destillates similar to PB Blaster, for example. The other organic compounds differ but I guess the idea is the same. No problems with the added graphite?
 
#15
So I got the nut moving - yes the nut and not the nut + rod. Good!

Now I noticed that the nut is actually at a slight angle to the heel of the neck, as if it is crooked. See the next pic. Would you guys recomend to take the nut off completely just to make sure it is put on straight and catches all treads? Counterclockwise movements are at the moment easier than tightening (clockwise).

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Is it safe to remove the nut at once? Should I take 1/4 of a turn and wait a bit like you would usually do when adjusting until it's off?

Greg
 
#16
Yes, it should be safe to remove it completely and all at once. I would check the nut threads and run a tap thru it to clean things up...may even need to be replaced if terribly mangled. If viable, I would lube and add a couple of spacing washers before re-installing.

Edit: if the cylinder itself is deformed, you may want to true the ends with a mill file.

Riis
 
#18
No, I doubt that. I bet the end of the rod is bent from someone trying to loosen it.

Take off the nut, chase threads, lube it and put it back. It'll be fine as long as it doesn't get bent back the other way. Clamp it into backbow and tighten it to hold there. Then loosen it to desired relief. If it needs tightening in the future, pull it into backbow to relieve pressure on the nut before turning it. Let the nut HOLD neck POSITION, not set position.

If you are always careful with this rod, using your hansd to bend the neck and remove tension from the nut, it will work for you.
 
#19
GregBEL said:
So I got the nut moving - yes the nut and not the nut + rod. Good!

Now I noticed that the nut is actually at a slight angle to the heel of the neck, as if it is crooked. See the next pic. Would you guys recomend to take the nut off completely just to make sure it is put on straight and catches all treads? Counterclockwise movements are at the moment easier than tightening (clockwise).


Is it safe to remove the nut at once? Should I take 1/4 of a turn and wait a bit like you would usually do when adjusting until it's off?

Greg
Click to expand...

Take 96's advice. It is correct.

The quarter turn "usually do" is a ridiculous maxim. Spin the nut until the adjustment is correct. If the nut squeaks,stop. Otherwise just make the adjustment and be done with it. Nothing bad will happen unless the task is performed by the mechanically challenged.
 
#20
Appreciate the feedback, thanks!

96 was right, I believe the rod is slightly bent at the end. The nut and threads are fine. I cleaned, added a washer and reassembled. Now, while holding in backbow I'm tightening in steps, letting the nut HOLD neck position as adviced by 96.

Should I better do the tightening steps over the course of several days or just go ahead until I know its tighened enough and then add relief over the course of some days until I hit the sweet spot? Originally, it had too much relief so I will be setting it tighter as it was (old bass, left in some attic for many years).
 

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