75 4001 repair

green_us90 · Post by **green_us90** » Sat Feb 03, 2007 5:48 pm

Hello All, I was wondering- would a standard switchcraft jack (say, one you could by to repair a Fender Bass) suffice for the mono jack of my '75 4001? It is going toes up recently.

Also, would any of you be kind enough to link me to the thread on the tail lift repair procedure (and I think it mentioned shimming the underside with quarters to minimise the preload that can cause lift)? Thanks for the help!

dale_fortune · Post by **dale_fortune** » Sat Feb 03, 2007 8:58 pm

The switchcraft mono jacks really never wear out. Usually what happens is the wires get twisted and the ground shorts out on the positive side or the tip (+) needs a little cleaning or adjustment. The bridge lift is cured by drilling 2 holes toward the rear of the bridge bass plate (then counter sink them) and put 2 new screws in.

doctorwho · Post by **doctorwho** » Sat Feb 03, 2007 10:17 pm

Dave, here's a link to my mitigation of a serious case of bridge lift:

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doctorwho · Post by **doctorwho** » Sat Feb 03, 2007 10:30 pm

The washers-under-the-tailpiece matter was discussed in this thread:

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green_us90 · Post by **green_us90** » Sun Feb 04, 2007 8:00 am

Thanks guys, I will try that. In the words of Ted,
"If you stick with a RIC tail piece, I strongly suggest fitting the route with a spacer. The 3 screws that sit under the bridge are usually the culprits here. If you set the tail piece in place without the screws, you will probably notice that the tail piece does not touch the wood right where those three screws go. When the screws are tightened (or overtightened) the tailpiece starts to bend right there. Newer Ricks don't have this problem as often but 70's vintage Ricks can have a gap under the tail piece of nearly 3/16". I use wood to fix this problem but you can use washers too. Just stack a few small washers under the tail piece on the screws until they fit snugly between the wood and tailpiece. BTW this will also improve the sound of the bass. Many older 4001s with weak E strings will simply spring to life just by doing this"

My E string does kind of sound dead so hopefully this will help.

Thanks again!!!

jingle_jangle · Post by **jingle_jangle** » Sun Feb 04, 2007 8:11 am

This kind of experience-based wizardry is only one of the things at which this site is soo good at!

rickfan60 · Post by **rickfan60** » Sun Feb 04, 2007 8:39 am

I just wish I knew that trick 25 years ago.

green_us90 · Post by **green_us90** » Mon Feb 05, 2007 5:08 pm

Well, I took the old girl apart, here is what I found:

There is at least a 3/16 (corrected from 3/8, d'oh!) inch gap between the underside of the tailpiece and the bottom of the routing. It is VERY obvious when looking down the 3ea mounting screw orifices, the gap is just STARING at you. Also, I put the 4003 tailpiece I have from my '97 4003 (home of a hipshot now) and the drilled holes in the bass do NOT line up with the holes on the 4003 tailpiece. I suspect if I were to get a hipshot that the holes would not line up as well, because the hipshot was a drop in replacement on my 4003. The holes on the 4001 are drilled about 1/8 inch closer to the headstock than on my 4003. ??? Spec tolerances?

Anyway here are some pictures for those who have not had the opportunity to compare a 4001 tailpiece vs. a 4003. As you can see in the pics the 4003 is much beefier in the webbing underneath the string ferrul holes, but still my 4003 was starting to lift, and I only strung it with medium tension Fender rounds. I have no doubt the preload of the un-shimmed mounting screws was the culprit. I have not measured the clearance on the 4003, however.
See links.

Thanks for the help, all!

http://fenderforum.com/userphotos/index.html?recid=41156

http://fenderforum.com/userphotos/index.html?recid=41157

http://fenderforum.com/userphotos/index.html?recid=41159

rickfan60 · Post by **rickfan60** » Mon Feb 05, 2007 5:12 pm

I am surprised that the holes don't line up. Which ones were off?

green_us90 · Post by **green_us90** » Mon Feb 05, 2007 5:15 pm

Ted, the three holes under the shimming takes place. When I put the 4003 tailpice on the bass, when you look down the tailpiece holes, you can only see the bottom 1/3 of the existing drilled holes in the wood. I'm as puzzled as you; if I had a better camera (will soon) I will try to snag a better pic.

green_us90 · Post by **green_us90** » Sun Feb 11, 2007 4:27 pm

Now that the bridge is bent back and reinstalled with the washer shims underneath said, all I can say is WOW, Ted you were right! Not only does the E string just boom but the rest of the strings project much better as well.

Thanks!

rickfan60 · Post by **rickfan60** » Sun Feb 11, 2007 4:46 pm

Isn't that awesome?! I was totally blown away by the effect the first time I did that mod. I am very pleased to hear it worked so well for you. It is a simple thing that makes a HUGE difference.