After replacing the heater core and repeating the disassembly process I'm currently having difficulty replacing the grey mat like insulation in the proper position that lives near the interior a/c unit. There is a small piece and a larger piece and I know I'm missing something but after a couple of hours I still can't figure this out. Any diagrams available or instructions that might help. Randy Mackrill Regina, SK. Canada '86 535i since new M kms.