If you want to try to stop crack growth, then blunting it is the thing to do. That may not be a step forward from an asthetic point of view, but it will keep them from growing for a time. The crack at the surface is likely to be behind the crack tip in the foam underneath, so consider punching the hole a 1/4 inch or so ahead of the crack tip.

Unfortunately putting a high strength adhesive like epoxy in the crack will not help. The repair will only be as strong as the foam itself and it is obviously weak. You would have to get up underneath the dash and seal the crack somehow to keep the adhesive from drooling out onto whatever is below.

There are vinyl/leather patch products around. Leatherique markets one. I have never used one though. I'm thinking something compliant to fill the crack, like caulk maybe, with a vinyl patch on the surface might be the best approach to slowing the cracking. My guess is that any thing you do will result in a highly visible repair and you will end up with a dash cover anyway.

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1985 300SD, 203,000 miles, dark blue

Lil Sarah says: "Poor old Grandma Blue Car...She's sad."