Hello all and hope your having a great new year. I thought I'd post an update to my earlier 4003s8 truss rod issue. Over the holidays I had a chance to work on my bass. This first picture shows the string heighth with full 8 string tension before the truss rods replacement. (sorry for the lousy pic but you can still see the problem) the gap was a good 3/16"+ and the neck had a substantial bow.
This second picture shows the older rods. Much to my surprise they were already 3/16" rods that the previous owner had installed, although they used the original acorn nuts and coupling nuts so the rod had been threaded to the older, smaller size...also, the coupling nuts had been cut down to about half of their length.
This third pic shows where the previous owner had inset the bridge to try and lower the action.
I bought 2- 3/16" rods from lowes and the acorn and coupling nuts from ace and made the new rods using a 10-24(3/16") die to thread the rods and then installed the new rods...total cost, about $15 including the rods, nuts, washers,die and a new nut driver.
Now, I'm slowly adjusting the neck but it is almost perfectly flat and the action is within a 1/16" off of the fretboard. I might even have to raise the bridge a tad. Here is a picture of my s8 with her Rickenbacker sisters, a 66 4005 and a 76 4001
Thanks to everyone for their input and I'll be able to play this bass again. A special thanks to Uwe and Dave. Uwe for his great info and Dave for the suggestion to not re-thread to the original specs. Cheers and a great New Year to everyone! David