I have a love/hate relationship with Rickenbackers. As a bassist, I absolutely LOVE the way they sound: many of my favorite records feature a Rick bass (such as King Crimson’s In the Court of the Crimson King, and Tool’s Undertow). But, I really dislike many of Rickenbacker’s design elements, such as their folded truss rod system they used back in the 60’s and into the early 70’s. They aren’t strong enough to control the curvature of the neck, and they tend to bend and break. I was recently brought a 1967 Rickenbacker 4001 bass with a broken truss rod, which had been shut away in a closet for years, left for dead. It was time to bring this bass back to life!
The problem: the treble side truss rod had broken, right at the anchor (which is typically where they break):
This isn’t as bad as it looks. Rick truss rods are easily removable. I simply removed the pickguard, inserted a long metal dowel to the truss rod channel, and then tapped it out with a hammer. On the headstock end, I placed a small spatula into the truss rod access cavity to provide a wedge for the rod to skate over, so the truss rod came out quite easily.
Here’s what a Rickenbacker truss rod looks like. It’s a single piece of steel, folded in the middle, and threaded on one end. When the rod is tightened, the nut pushes against the truss rod anchor, which then pushes against the unthreaded end, which then causes the rod to bend and expand. This expansion is intended to counteract the string tension pulling the neck in the opposite direction. (This is similar in concept to modern double acting truss rods, which use an anchor on both ends and are much stronger.)
You can see in the first picture that the threads are completely toast, so I would have to cut that back to get to some fresh metal. Rickenbacker truss rods are pretty long, and can be safely cut back 5cm (2″) and still function properly. Using a Dremel equipped with a metal cut off wheel, I cut the truss rod back about 2.5cm (1″). Woo, sparks!
Next I used a 10-32 die to cut new threads onto the rod. I had to be careful with this, as I learned very quickly just how soft this metal was – the truss rod was actually twisting and bending as I was cutting the threads!
Now that I had a function truss rod again, I put it back in the neck the same way I removed it – just tapped it in with the hammer and metal rod. Since the original truss rod nut was wrecked (the broken piece of truss rod was fused inside, and couldn’t be removed), I tried a bit of an experiment. One of the problems with the Rickenbacker design is that the rod’s ends tend to bend down into the neck, digging into the wood and making it impossible to fit a truss rod tool around the nut. So instead I used two Fender style truss rod nuts, which use an allen wrench instead of a nut driver, so there would be no problem getting the tool in there.
This worked like a charm. I was able to get the neck to a reasonable degree of straightness, and the extra length of the truss rod nuts spread the downward pressure out so that there is no risk of damaging the wood (a common problem with this design using the standard nuts). Right on!
This bass could still stand for some fretwork, as the neck had sat for many years in a bowed shape, and the wood had taken on a shape that wouldn’t be fixed simply by adjusting the truss rods. But, now that the truss rods are functional again, it’s actually playable. With just a wee bit of extra work, it could play like a million bucks. That sounds like a winner to me. Huzzah!