J Bass neck woes

[Jondeeman]

I was hoping to pick the brains of the great and good of this site. I have MIM 2010 Jazz. I replaced the stock strings with D'Addario flats last year. There was a little more string tension, and I attempted to adjust the action. TBH I didn't get a great result and the bass was put to one [font=Calibri][size=3][color=#000000]side. It’s been a crazy year and my main bass has sufficed. I’ve now got the bass out, determined to make things right and fix the silly action issue…[/color][/size][/font]

[font=Calibri][size=3][color=#000000]I first changed to a spare set of Rotosound strings and set about a set-up. The problem is that I just don’t seem to be able to adjust the neck at all. The Allen screw turns, but nothing seems to happen. It’s almost as if the truss rod has become detached.[/color][/size][/font]

[font=Calibri][size=3][color=#000000]So, questions are… is this what has happened, or am I missing something obvious? And (obviously) what can be done about it? I’m okay with general maintenance, and have put together a couple of bitsa basses, but this has me at a loss.[/color][/size][/font]

[Thunderbird]

The first thing I would be doing is checking how straight the neck was with a straight edge or hold your string down at the 1st and last fret and use it as a straight line.

Are you trying to adjust the neck with the strings up to tension? if so slacken them off and just turn the adjuster in small amounts say a quarter of a turn a day
then if that helps before going any further

[3below]

how many turns have you given truss rod adjuster? If just turning and turning is there any resistance? if not, it sounds like stripped threads - bad news

Plan A -
Slacken strings off, unscrew truss rod adjuster - does it extract? If so check threads on adjuster and rod. If you are lucky both are ok. If both ok, grasp bass neck with one hand at nut, one near body / neck join. Apply knee to middle of neck on fingerboard and push gently - you may hear creaks and 'cracks', do not worry. This should re-establish concave setting of neck and put truss ros at correct starting position. Fit truss adjuster back in, tighten until some resistance. String up, check action, loosen strings, tighten truss rod slightly, etc etc until all is ok.

If Plan A fails;

Plan B start as as plan A. Check if truss rod thread OK and the adjuster is stripped (in an ideal world this is what should happen, the adjuster should be softer metal than the rod), replace adjuster and move to plan A.

If Plan B fails;

Plan C - truss rod thread stripped - seek luthier advice / help or new neck needed, whichever is cheapest.

Hope you are lucky

Edited August 15, 2014 by 3below

[HowieBass]

You're tightening with a clockwise motion (righty-tighty) and little/no string tension on the neck I hope? With no tension pulling on the neck you will probably have a slight back bow (which is good) if the truss rod is doing its job... if it's still got a forward bow then something's wrong with the hex bolt or the rod. Have you got the right size allen key/hex bolt for the bullet adjuster? I believe there can be slight differences between Fender basses (some use a metric sized allen key, some use an imperial sizing depending on which factory put it together) so make sure you've got the right one. If it turns with no resistance as you try to tighten it then follow the advice given above. Good luck!

Edited August 15, 2014 by HowieBass

[3below]

Excellent advice above, I had forgotten the 'stuffed' allen key effect - either the adjuster hex socket or the allen key could be rounded. This would be a 'good' result, both are vastly cheaper than the worst case.