Replacing under-dash sound deadener?

[dieseldan44]

Pulled my evaporator box and now Im staring at some crumbling 25 year old sound insulation. The main spot where its cracking is under where the evap box sat.

Anyone replace this with anything? I could use dynamat or something like that, but I'm worried about the lack of 'hard top' that the factory stuff has, or messing up the fit of the evap box with thicker material.

All ideas greatly appreciated! Someone surely has gone down this road before :-)


An aside - so glad I pulled the evap box - its not hard. It was full of dirt and stank. Using dmorrison's instructions it took me 9 hours to get the dash off, evap box out, and totally apart on my bench. Im going to replace the evaporator, probably the heater core, expansion valve and clean the snot out of it.

Pic 1: Naked dash area of Tex. Cracked and crumbling insulation can be seen under where the evap box goes.
Pic 2: Evaporator caked full of crud. Theres like 1/2" on there.
Pic 3: All pieces of evap box apart. In the foreground L-R are the evaporator, fresh air section and evaporator bottom. Background L-R is the front with the vacuum switched and the heater core standing up.


thanks,
dd