I think I may have a leak in the firewall in my 98 disco, I thought it was the AC compressor dripping to much but now it seems to be strongly coorelated to heavy rainstorms. There was a wire from an amplifier from the previous owner that I believe goes through the firewall. It seems like the water comes up through the passenger seat floor and flows to the rear on that side. Any thoughts?

 

Check you a/c drains for clogs, then look for holes in the fire wall. I am still willing t bet it is your drains. raining=more condensation=more water from a/c

 

D1's were known to crack the welds where the bulkhead is welded to the floor, might want to have someone who experienced with this inspect it.

 

Crawl under the truck and look around the bell housing (where the transmission mates with the engine) and look for two rubber drain tubes. They should have nipples on them, squeeze the nips and drain the water.
Take a pipe cleaner and ream the tubes out to remove any dirt.

 

Is the ac drain the same thing that spike described?

 

Yes, those are the A/C drain tubes. I would start there.