Setting up a 4001 fretless

[Rickenslayer]

Hi,

some time ago I've bought a 4001F. The previous owner bought it in 1981, he wanted to learn to play the bass - and he never started.
So the bass was sitting in some cupboard for 30 years
It is in very good conditions, looks like new. Before he offered the bass for sale he got it serviced. Setup and new strings.

So far so good. Now I noticed that the setup could be better (I have to adjust the neck on all my instruments at least twice a year, always
in spring and autumn). So I've removed the TRC and what I saw was.....surprising. See fotos:




The metal plate is not sitting where it is supposed to be. However, it's sitting firm and does not seem to be broken. The nuts are also sitting firm.
Unfortunately the lower side of the nuts is so close to the wood that I can't use my Rickenbacker wrench to turn the nuts. I might need some flat wrench.
I know how to set up the truss rods of a 4001. But maybe the guys who did the setup didn't know (as so often ).

Any recommendations? The neck is not flat now, the nuts need a quarter or maybe half a turn. But I don't know how to proceed and I don't want to
make things even more worse.

Thanks!

[ken_j]

Welocome to the RRF forum Chris. Hopefully Paul will chime in here.
I would loosen the string tension and the the truss rods. If the ends of the rods are not bent you should be able to slide them back into the neck. These are the old style hairpins-type rods. You cannot adjust the neck by simply turning the rods but need to bend the neck into position then snug the rods at that point. Use the search function and you will find a detailed procedure for adjusting old style rods. Failure to do so may result in popping the fingerboard off the neck or simply cracking the neck.

[cassius987]

I would try to get the rods re-seated before adjustments are made but I am no expert on doing this task--just my gut reaction, you don't want the rods all bent out of shape in their channels before trying to get them to work. I know if everything is loose and free-moving they should not be hard to reset, but you will probably have to take off the pickguard and strings to get to the acorn nuts at the body end. As far as little space to work with in the cavity Pick of the Ricks sells a thin-walled tool by Dunlop.

[Rickenslayer]

Thanks.
Maybe the format of my post is a bit unfortunate. Please note that there is more text below the pictures...

[Wiker]

Thanks.
Maybe the format of my post is a bit unfortunate. Please note that there is more text below the pictures...

Those old style truss rods and the spacer bar are loose in the neck, only held in place by the pressure when the rods are tight. If the nuts are loosened completely you should be able to push the rods further into to the neck, and push the spacer bar in place.

Relax the string, force the neck to a back bow, and unscrew the nuts. Clamping the body onto a table makes it easier to force the neck back with one hand while screwing with the other. To push the neck back, don’t grab onto the headstock but press onto the fretboard.

Forcing the neck back like this will relieve pressure from the rods, and by that the nuts might raise enough to get the wrench onto the nut. If you still can’t get the wrench on you can use pliers to turn the nuts to get them off.
With the nuts off you should be able to slide everything in place again. I would put on some steel washers to prevent the nuts from digging into the aluminium spacer bar.

When tightening up those old style rods again you’ll have to force the neck to a back bow, and hold it like that while tightening the nuts. Every time you want to adjust the rods you must hold neck in a back bowed position when adjusting the nuts.

Here is a trick from aceonbass that makes it easier to get the wrench on to the nuts in the future:
viewtopic.php?p=676478#p676478

And here are some small fixes I did to make the rods and nuts run easier, and you can also see that I did the trick with the nuts:
viewtopic.php?p=687140#p687140

[deblase4001]

Probably a good time to pull the rods and inspect them. The ends may need to be straightened. Looks a lot like my 75 4001 did when I looked under the TRC. See my recent thread:
viewtopic.php?f=2&t=404031

It was easy to fix and I had great results setting up the bass afterward.

[ken_j]

If you need or decide to pull the rods be sure to clamp the end of the fingerboard so as not to pop it off or crack it prior to pulling the rods.

[johnallg]

I know if everything is loose and free-moving they should not be hard to reset, but you will probably have to take off the pickguard and strings to get to the acorn nuts at the body end. As far as little space to work with in the cavity Pick of the Ricks sells a thin-walled tool by Dunlop.

Josh, these are the old style hairpin rods and will not have acorn nuts at the body end. Only the newer 4003 basses (1983ish and newer) have the double nutted rods.

[Rickenslayer]

Hi again,

quite some time passed since I opened that thread. However, the problems are still there.
Maybe some of you guys have another hint for me?

I was able to remove the nuts and the truss rod spacer. It looked pretty bad, the truss rod and the nuts have digged quite deep into the aluminum.
I also was able to push back the bass-side truss rod into the neck (see my opening post for pics).

The thread of the truss rods looks good on the outer part (first 15mm or so) but is damaged then. To be sure that I won't get near the damaged
part, I've made two "rectangular washers" from aluminum. Assembled together, it looks like this:

http://i303.photobucket.com/albums/nn14 ... G_0493.jpg

But, as you can already see on that picture, the truss rod spacer is sitting in some weird angle. This happens as soon as I tighten the nuts.
The truss rod on the E-string side is kind of pulled out of the neck. Why?

The truss rods themselves don't look too bad. At least from what I can tell:

http://i303.photobucket.com/albums/nn14 ... G_0498.jpg

Anyway, I still can't find a working setup for that bass. Bending the neck into position, then tightening the nuts generally works. I tightened
them with quite some force, but not too much.
The neck still has too much relief. String action still is too high, especially between the 4th to 8th "virtual fret" (up to 1.5mm I'd say)
It somehow seems that that E-string side truss rod does not do anything at all. I can bend the neck further down, but I can't turn the nuts
any farther (i.e. without using even more force).

Is there anything I'm doing wrong? I followed all advice I could find for setting up an old-style 4001. But the result is disappointing
Ah, another thing I should mention: As soon as I start to lower the bridge, I reach a point (still high action) where I get dead notes around
the 19th thread. Sliding up there kills the tone when I get close to 19th. Pushing down the string there results in a tone like a muted note.
The string can't oscillate. Beyond that point (20th, 21st) it works again. Could it be that the neck has some hump there? Could it be related
to the truss rod problem?

Thanks for reading that much text

[doctorwho]

Chris, PM Paul W. and have him look at this thread. I'm sure that he will have some good advice for you on how to start on this.

[aceonbass]

Not necessary to contact anyone else. This is a simple procedure. Apply pressure with a flat head screwdriver against the bass side of the truss rod nut thrust plate, and tap it with a hammer until the thrust plate seats against the nut side of the truss rod cavity. Now you can adjust the truss rods per the old style procedures.

[Rickenslayer]

Dane, please read what I wrote about the problem, don't just look at the pictures

The bass side truss rod is driven out of the neck when I tighten the nut (it's fine with loose nuts).
Working with a hammer there would end up in a complete disaster!

[aceonbass]

Okay...well the rods need to come out so the threaded ends can be straightened and chased with a die. Since you can't get a nut driver over the nuts, you'll need to use a 1/4" wrench to loosen them. I still think it would be a good idea to tap the block back into position if only to make it a little easier to remove the nuts. I'd dress all the flat surfaces on the thrust block and nuts with a file and turn the truss rod nuts on one end per my previously mentioned suggestion. Use steel wool to remove any rust on the rods and re-arc them before reinsertion.

[jingle_jangle]

Hi, Chris. Got your PM and there's a few things that should be done. First, remove strings and truss rods.

Let the bass sit for a week or so in the case to settle the neck. Inspect for cracks near the nut. No cracks? Good.

Check to see if the spacer will fit into the cavity and that it will snug up straight against the truss rod pocket, without the rods in place. It does? Good. It doesn't? File both ends and radii until it does. You should have to remove very little--perhaps 1/32 from each end, MAX.

Now you're going to blueprint those truss rods like the ghost of Smokey Yunick. Get out a cigar and make sure your fingernails are dirty!

Make sure the threaded portion of the rod is straight, not bent and/or distorted. If bent and/or distorted, try to straighten without damaging threads. If this is not possible, or if the threads or rod itself feel weak, hacksaw off the entire threaded portion, rethread it, shorten the other end of the hairpin rod by an equal amount, and grind or file a bevel on the face of the unthreaded end to about a 15 degree angle, with the acute edge on the down side.

With the business end of the rod blueprinted, you can address the rods themselves. Clean both rods with a wire brush, remove any tape from the inside of the rods, and separate the rods while removing any residue with a rag dampened in denatured alcohol or moonshine likker. Cut two long, 3/16" wide strips of vinyl electrical tape. Try your patience to the limit by lining the insides of both rods with this tape, then lubricate the inside faces of the taped rods with a light coat of vaseline.

Now check the arc of each rod--it should be about 2" in the center, with the two ends facing down and the threaded part of the business end on the bottom. Time to re-insert the rods into the neck.
Screw a nut onto each rod about 8 turns and then lightly lube the rod with some more vaseline. LIGHTLY!!! Now carefully slide the rods into their slots. Keep the nuts on and tap gently with a hammer as required. You may wish to protect the headstock by taping a piece of shim stock or thin plastic, onto the area where the rods can contact while you're sliding them in. Nothing wrong with holding them straight with your hands while sliding. Slide them in until the shorter end of the hairpin is flush with the end of the rod pocket, and the threads are exposed.

Remove the nuts and lightly lube the threads, carefully replace the spacer/thrust block, and replace the nuts. Tighten about 1/2-1 turn and begin the adjustment process by continuing to tighten the rods, nudging the neck back by hand, a half-turn at a time until the neck is about one millimeter (.040") high in the center. Now install the strings and tune to pitch. Let rest a day or two.

Come back, evaluate neck bow, and tighten/loosen the rods 1/4 turn at a time, waiting overnight before checking again.

This basic setup may take a week of evenings before it's perfect, but it will last!

[Rickenslayer]

Edit: Already available viewtopic.php?f=2&t=404031&start=20
Is it right that way?

------

okay, many thanks!
Sounds like some major surgery

Do you (or anyone reading here) maybe have a photo of a ready-to-be-reinstalled truss rod?
I'd like to see how it's supposed to look (2" arc and stuff). I would feel more comfortable than with only having the theory in mind.

Cheers!