[C320-list] Leak at Instrument Pod Support Tubes

[Dave Hupe]

I've developed a slow leak related to one of my stainless steel tubes for the instruments/engine control panel wiring that extends into the cockpit floor.   This just showed up after uncovering the boat. The leak is evident by a trail of seepage down the back inside wall of the aft bedroom (apparently dripping into the pan above the bed that covers the steering idler pullies, with the water then slowly working its way out the aft end of the pan). 
Each stainless tube has a bracket at the bottom secured with 2 vertical bolts (Philip head) extending into the cockpit floor and one horizontal bolt on each bracket that seems like a "set screw". 
Does anyone have experience dealing with leaks related to these tubes that can give advice? Are the vertical bolts each thru-bolts with nuts underneath accessible thru the pan covering the idler pullies in the aft stateroom, or are they screwed into plates in the cockpit floor?  Have you packed the holes with butyl rubber and then reinstalled the brackets? 
Thanks in advance for the advice.
Dave Hupe
1994 Cat 320 (#32) "Mayan Sun"
Holland, MI