rewire older speaker internal wiring?

Different brands of caps will have totally different sonics.If
you get in there to do it,maybe try Solen first.They're kinda
neutral.There might be stuff on the net telling you what to
expect from what brands in that speaker.Sometimes a cap change
can make it sound like a different company made it.Same thing
goes for amps.I hope this link helps out. Link>>>[http://manuals.harman.com/JBL/HOM/Technical%20Sheet/4311B%20ts.pdf]

Any good wire should be ok.Good tight connections are important.Also,don't use higher uf,or mfd values on the caps
unless a real pro tells you its ok.That will pass lower frequency's to the drivers possibly blowing them.A little higher voltages should be ok.There's a lot of JBL fans on the net that may have places for help.

Another link>>>[http://www.lansingheritage.org/html/jbl/jbl.htm]

On this link I sent you on the 23,I think they show the crossover coming out of the front,when it looks like it may be
mounted inside.There might be a cover plate hiding the two screws?Their diagram doesn't look 100% right.
[http://manuals.harman.com/JBL/HOM/Technical%20Sheet/4311B%20ts.pdf]