Truss Rod Problems
Broken Truss Rod / Rod Turns Freely
In most cases, this is a biggy. You may hear a clicking sound when attempting to tighten a broken truss rod, others may spin freely, offering little to no resistance.
Removing most truss rods requires removal of the fingerboard, which in turn, requires a complete refret and finish work. The cost of replacing truss rods will almost always exceed $500. At this point, pricing a factory replacement neck may be in order if the instrument is relatively new and still in production. For inexpensive instruments this can be the end of the line as repair cost may exceed replacement cost.
Sometimes you get lucky and the neck will still be playable and have acceptable relief even with a broken truss rod.
Truss Rod Is Hard To Turn
Normal truss rod adjustments do not require hiring a strong man to turn the wrench. When a truss rod nut is difficult to turn it could be that the rod has met it's limit of adjustment. Truss rods can break if too much tension is placed on an already maxed out truss rod so caution is warranted.
The truss rod is as tight as it will go and the neck still has way too much relief in it.
Some older, untouched instruments may also show resistance when the threads between the rod and nut corrode. When making adjustments to older instruments it is advisable to lubricate the nut with graphite to prevent seizure and damage.
If you see no change in neck relief when tightening the truss rod it's best to stop and seek professional advice. A maxed out truss rod may continue to turn but in actuality it may merely be compressing the wood behind the truss rod nut.
- The neck (wood) is lax and does not resist string tension adequately
- The neck has taken a set and moves very little with or without string tension (warping)
- Heavy tension has caused excessive upward bow that can not be removed with a truss rod adjustment
- Poor quality truss rod
If a truss rod nut is difficult to turn I lubricate the threads before preceding. I may also remove string tension to reduce resistance and in some situations, clamp the neck in a slightly back bowed state prior to tightening the nut.
When no further truss rod adjustment is available and the neck still has too much relief I may choose to plane the fingerboard and refret using fret wire with a larger tang. Planeing straightens the fingerboard and larger fret tangs create additional compression and stiffness the neck. If, however, the neck shows itself to be weak and spongy, satisfactory results may not be obtainable using this method.
This is a situation that requires physical examination to determine the best course of action.
Stripped Truss Rod Nut
When the truss rod nut is not welded to the rod (like those used on two way truss rods), the nut is backed out and replaced.
When adjusting truss rods on vintage or problematic guitars I prefer to lubricate the threads with graphite to help prevent thread seizure in the future.
Back Bowing / Not Enough Relief
Ideally, loosening the truss rod should allow the strings to pull it upward and create more relief in the neck. Unfortunately some necks can actually back bow, even with the truss rod completely loose and the instrument tuned to pitch.
In this situation a single action truss rod can offer no help.
When the neck is only slightly back bowed or simply dead flat, using heavier gauge strings may create just enough tension to pull then neck straight or increase the relief.
When a neck remains in a back bowed state with no string tension (and the rod completely loose) I may choose to plane the neck.
As with other neck issues, this is a situation that must be evaluated.
I am more inclined to believe improvement is possible when the instrument is older and the neck has settled. The reason for this assumption is simple ...when dealing with a very new instrument who's neck is moving unpredictably, it remains likely that the neck could continue to do so, making a seemingly perfect repair only temporary. It's hard to pour over $300 into a repair only to find it will be required again in another year or two. At this point, when applicable, a replacement neck seems a wiser investment.
See Also: Adjusting Truss Rods
Acoustic Guitar Repairs
- Action / Set Up
- Bridge Plate
- Bridge Pins
- Buzzing - Noise
- Care / Maintenance
- Convert Rt. to Lt.
- Fret Replacement
- Fret Types
- Neck Damage / Issues
- Neck Angle
- Neck Resets
- Part Glossary
- Strap Buttons
- String Changing
- String Choices / Effects
- Truss Rod
- Tuning Machines
- Tuning Troubles