A pocket of significant rust (flaking away) at lower front corner of both aftermost side windows (inside the car), similar flaking away at aftermost edge of underside of the rear wagon storage compartment (the one with the little trapdoor flap for entry), and two significant patches of it on the underbody beneath both front seats. The underbody patches are evident because of bubbling beneath the undercoat, spongy to the touch, and each about 1 square foot in area. I also observed water dripping from the rusted spots at the windows during a recent steady rain.

Several questions are indicated:
- what are the possible water entry points that would lead to this rust pattern? Is there a pattern for this vintage Volvo?
- what are the cures for the rusted spots? Obviously I'm concerned about the structural implications of the underbody rust.

Thanks.