Like Gypsy guitarists seeking the "duende", surf guitarists chase "the drip". This cavernous percussive sound is a defining element of surf. A good drip really sounds like drops of water falling in a cave. It's most excellent, Bill & Ted!
I have not had the chance to use a real Fender outboard reverb but I have read that turning up the control called "dwell" sends a stronger signal to the springs which initiates the drip sound. I have tried many different reverb pedals to get a drip sound, but results haven't been that great. The best built in drip I have actually played was on a Quilter Micro-Pro solid state amp. What can I say?
I think the key to getting this sound may be related to gain structure. Running lower output pickups loud into an amp with some headroom seems to drive the reverb harder while the amp itself stays clean. I had some work done on my old Princeton Reverb. The repair guy fixed the tremolo and replaced the power tubes. I had to replace the original reverb tank because you couldn't touch the amp without setting off the spring noise. Repair guy said the new reverb tanks aren't as splashy as the old ones. He was right, but that's not the whole story. I saw some guy on the internet talking about getting a good tone from a Deluxe Reverb or a Princeton. He suggested keeping the bass and treble settings equal. I tried this and it does yield that classic Fender "thump & chime". Using a strat with 90s era AVRI pickups, I turned the guitar volume to about 8 on the middle pickup. Amp was at 3. Treble and bass at 7. Reverb at almost 5. Dripped like a leaky roof.
So that's my story... Lets Go Drippin'!