Restoring a steering wheel can be a tough job. We do two or three a year in our shop. First step is you need to widen out all cracks down to the metal internal ring. I use a wood rasp. Second you need a two-part epoxy (we use PC-7). Mix it up and press in as much as possible. You want to bond to the metal ring and the wheel. Then you sand it down with 80 grit, reapply if necessary. Finish sand the entire wheel with 180 grit. We then apply 2-3 coats of a good two part fill prime (automotive grade, not aerosol), wet sand with 400 grit, re-prime if necessary. I use base coat/clear coat as the final finish. Keep in mind that the material the steering wheel was made out of is shrinking, and will continue to shrink depending on conditions. You will more than likely see cracks start to form again in a year or so. The only way to permanently fix them is to have them recast ($700-900)
