4003 S-curve neck?

[Ricfin]

I posted the same thing on the official Rickenbacker forum. I have not received any replies so decided to try here also. I hope it is not against any rules.

Hi all, I am helping a friend with a 1995 4003 bass. It has developed a fret buzz and high action problem. I thought it would be a simple truss rod adjustment but I was wrong.
I measured the neck with a straight edge and discovered that the neck has developed a bow. Bow remains in some degrees even the bass is unstrung. The truss rod works but it affects only the first 5 frets. If I tighten the rod it creates a back bow in that area creating a S-curved neck. This results fret buzz when playing, making bass unplayable in the first 5 frets.
The other effect of the up bow is very high action (the bridge is bottomed out).

If you know a thread that covers my particular problem please direct me to that.

I was thinking about my options, would a new truss rod help?
Or is the problem in the neck wood, fatigue perhaps. Would some kind of bending with heat be any use?

Any suggestios are welcome.

[inhuien]

Have you looked here? search.php?keywords=truss+rod&terms=all ... mit=Search

[ilan]

I pulled the rods out of my 4003 (it's simple if you know what you're doing), they were curved, so I reversed the curve - inserted them back into the neck with a back-bow curve. Before, the neck was a ski-slope. Now the neck is arrow-straight and has been stable like that for several years since I performed this, and the action is ridiculously low, like a Les Paul that was set up for an 8-year old girl

[Ricfin]

Did you just rotate the rods 180 degs and inserted back or did you reverse the curve with hands before putting them back?

I pulled the rods out of my 4003 (it's simple if you know what you're doing), they were curved, so I reversed the curve - inserted them back into the neck with a back-bow curve. Before, the neck was a ski-slope. Now the neck is arrow-straight and has been stable like that for several years since I performed this, and the action is ridiculously low, like a Les Paul that was set up for an 8-year old girl

[ilan]

I just rotated them 180 degrees inside the channels. At first I thought I should straighten the rods, but John Hall said they were pre-bent at the factory for a good reason. Actually there's no need to pull them out. After a few trial turns you can feel when they're in a back bow. Easy fix that turned a non-playable bass into a bass that practically plays itself. The strings BTW are DR Low Riders, so the neck can take the pull of standard tension strings now.

[Lost Coyotes]

I had a similar thing with a 1986 4003. The "S-curve" manifestd itself as like a hump around the 14th fret to the 20th fret, then again near the nut. It was frustrating to attempt to set it up.
With lots of input from this forum, and I think (If I remember correctly) that Mr. Hall was a big part of it - a solution came:
I removed the strings and trussrods, laid the bass out on it's back and using a straight edge, manually moved and clamped the neck into "straight". Then I "over-did" that just a bit around the 14th-20th frets. I took some sort of a hot light and placed it a few inches away from the area to be straightened, and let it sit for some hours, repeatedly checking to be sure it wasn't getting "too" hot; or so hot as to be otherwise damaged.
Once it cooled for a long while, I removed the clamps, put in the rods after cleaning them up and re-"arc"ing them, restrung it and set it up as per spec.
It actually helped a LOT, and was I relieved at that, because it was almost useless as a player as it was.
I hope this helps, and good luck to you.
(I'll see if I can locate that thread from long ago and double check my info)

[ilan]

This procedure softens the glue that holds the fretboard and neck together. Very clever.

Manu described an S-curve and very high action - he may need both procedures.

[Ricfin]

Thanks everybody for your input. Looks like my initial thoughts were in a right direction. Here is what I am going to do:
1) Take out the truss rods and inspect them.
1a) If they are mechanically broken, buy new ones and replace them.
1b) If functional, rotate 180 deg and insert back.
If this works, problem solved, if not go to phase 2.
2) Remove truss rods, clamp the neck to a slightly backbowed position and heat with something.
3) Take the now totally screwed bass to a professional (should done in the first place)

I will let you know what happens. I can do the phase 1 during this weekend.

This procedure softens the glue that holds the fretboard and neck together. Very clever.

Manu described an S-curve and very high action - he may need both procedures.

[ilan]

Take some pics, it's always helpful. Good luck.

[ram]

Clamp the fretboard and good luck with the project. Where are you located?

[antonius]

I had an S curve on my 1975 4001, with a hump from about the 9th to the 14th fret and another one at the nut, with a horrible dip centred at around the 4th fret. I ended up having the board levelled and re-fretted and re-finished. It cost some money but it sorted the problem out pretty well.

[Ricfin]

I just performed trussrodsectomy. The operation was successful and the patient is feeling only mild soreness in the neck area. Seriously, the truss rods came out quite easily and look good to me. They are not curved so rotating them is no use. I put some pictures into my Dropbox. The pic with strings shows the starting point, the sting action when there is no string buzz. If I tightened truss rods any, buzz would manifest at frets 1-5. Then here are some pictures of the extraction process. The last picture shows the upbow at 12th fret when there are no strings or truss rods.

I have a feeling that pre bending the rods is not enough to force the neck to go straight. It is easily tested but I am afraid I must start thinking about some kind of clamping apparatus with a heat source.

Pictures
https://www.dropbox.com/sh/nxwulowf5wrgo2k/qekZqJlVPV

[jps]

I just performed trussrodsectomy. The operation was successful and the patient is feeling only mild soreness in the neck area.

Paging Dr. Mendelson, please come to the Operating Wing!

Jason-TR_800_2332.jpg

It's a boy, Mr. Walker, it's a boy!!!

[ilan]

I like your new avatar, Jeff.

[jps]

Pure as the driven Snowglo!