The problem with cracks is they have a tendency to propogate and continue getting longer until you get complete failure.
In other applications, the best way to prevent this crack propogation is to drill a hole through the plastic at either end of the crack, its very important to be either the exact end or beyond it.
You can then fill the crack and the drilled holes through other means (ABS filler and solder iron has been suggested)
Best way to get hold of some abs is to raid a source of scrap plastic, you may even find some red, ABS is one of the most common plastics in use today.