4107 Evaporator-Heating Unit Assembly = Help Needed

[Vanderbus]

I'm trying to remove the evaporator and the heater core from my 4107. We drained fine, removed the plywood access door fine, disconnected all the requisite hoses and wires fine, and then ran into trouble.

The assembly - and it's my understanding from the manual and from looking that the evaporator, heater core, and blowers are on the same big frame - is held in place by 6 hex bolts underneath the coach. Well, 5 of the 6 bolts are spinning without backing out, and I don't know what to try next.

My guess is that there are weld-nuts on the assembly frame and that the welds broke loose, but I can't get at the nuts because of the evaporator and the blowers (plus the dirt, grime, pencils, and candy wrappers). Any suggestions? I don't feel safe trying to cut off the bolt heads underneath the bus without getting the bus up off the ground, so that's out for now. Other ideas?

Thanks in advance,
Joe