Inside nearly every modern guitar and bass neck is a truss rod: a long, adjustable steel rod designed to counteract string tension on the neck. Without it your guitar strings will eventually bend your instrument’s neck into an unplayable banana-shaped object. They are usually pretty sturdy, but if they are abused they can sometimes break. Our friend, Brandi Wynne of the band Ozric Tentacles picked up this ’72 Fender Jazz Bass neck with a broken truss rod and asked us to fix it. Here’s how we went about removing and replacing a broken truss rod.
This neck is equipped with a single-acting truss rod installed into a channel in the back of the neck, which is then filled with a walnut “skunk stripe”. So I had to remove that first to gain access to the rod itself. I generally use a heat gun to melt the glue – just gotta keep it moving so I don’t burn the finish!
Once the glue joint was separated, I drilled some tiny holes into the skunk stripe, screwed a wood screw into the walnut and used a specialized tool designed for pulling knobs to begin lifting the piece out of the neck. We oftentimes use tool designed for a specific job for something beyond it’s intended purpose – sometimes the wrong tool for the job is the right tool for the job!
I only used the knob puller until I was able to get under the skunk stripe with a 1/4″ chisel, then used the chisel to get the rest of it out.
With the skunk stripe removed I was able to easily tap the rod out of the neck.
To replace the broken truss rod, I opted to make a new one from high strength steel. I cut the new rod to length, then used a die to thread each end – one for the anchor, one for the adjustment nut.
The biggest reason I removed the skunk stripe is because although the truss rod has to be glued in, it always needs to be able to move freely inside of the neck. An insulator tube must be used to keep glue from getting onto the rod, but the tube itself is larger than the rod’s access holes at each end of the neck, so I placed the tube inside of the truss rod channel, then fed the rod through it.
Then I glued the skunk stripe back into place.
After I cleaned up the excess glue, I touched up the clear finish and polished it back out, making sure it looked as close as possible to how it arrived to the shop – battle scars and all!
Once the neck was all put back together I bolted it up to our surrogate body and Plek‘d it, to level the frets and make sure it plays clean with no dead spots.
Good as new! Thanks, Brandi!
[A note from Benjamin: I experienced a weird bit of synchronicity when Aaron finished up this job, and I was preparing to ship it out. Ozric Tentacles had just put out a new record, which I put on right as I was making up Brandi’s invoice, not knowing that Brandi is IN Ozric Tentacles. I’ve been a fan of their music for over 20 years, and now they are sending their instruments to us to work on! Many miles away something crawls to the surface of a dark Scottish loch…]
