When I glue ABS parts together, I use the PVC pipe cement. It will dissolve the plastic and weld it together. You do have to be careful not to deform the plastic.

One technique I've found that works quite well is to just glue enough spots to hold the joint in alignment. Then cut some strips of .5 oz fiberglass cloth wide enough to span the joint and give about 1/4-1/2 inch overlap. Brush a layer of PVC pipe cement on and then put the cloth over the cement before it dries. Now brush another layer on top. The glue will penetrate the glass fibers, and when it dries, it leaves a hard plastic impregnated into the fibers, as well as bonded to the original part. Makes a flexible, yet durable joint. I also use this method to repair cracks in ABS parts (cowls for example).

Brad