I have a mobile home that I'm working on,a 1976 champion.it had a bad water leak in the hot water tank closet.I need to replace all the flooring in that area.my question is this:is there a way to replace the flooring underneath the walls short of taking the walls down?thanks for any help

The walls in a mobile home are little more than partitions. You could try to cut under the wall with a flush cut SawsAll but you will have a tough time sliding in new flooring material. So to answer your question, yes it can be done, just not easily.

I had the same problem in a trailer that I lived in the quick fix solution I used was to cut the flooring up to the walls but leave the little piece under the wall. Next cut some 2 x 6's or 2 x 8's to go between the floor joists so it gives you a lip to nail the new flooring to.
hope this helps