There is a method of repairing this problem but you have to anticipate that this fault can occur. So now it has happened you will know what to do, and that is before you fit the pad cut off some of the solid rubber that is destined to be waste and ground off and keep it to one side. And if the worst should happen and you end up with some air pockets showing though I draw the line at repairing two any more I scrap the pad.
You select a drill size that will just remove the hole but it must be very sharp to drill rubber, next use a high speed low voltage drill something like the type that starts with D and ends with L. Drill the hole out to a depth of about one eighth of an inch next using a hole punch the type usually used for punching holes in leather and cut a small plug from the rubber you saved from the pad in the first instance. Make it slightly larger than the hole you have just made. Now run some Bicycle inner tube patch adhesive into the hole then work the plug into the hole while the adhesive is still wet, while wet it acts as a slight lubricant. Let it dry I leave it about 24 hours cut the plugs excess off with a sharp knife and finish with the abrasive as the rest of the pad. I will say that the repair is not 100% invisible but it is about 95% because sometimes the patch glue does not dry totally clear.
