Not sure ball joints can be overfilled with grease, usually it's like that it just pushes itself out when full but I was under my truck the other day 5 months / 10,000 miles after changing the top and bottom and one of the boots is completely split and the other looks wrinkled and dry and as it would work too. I'm just driving my truck on the street, I don't know what happened here. The ball joints were the main reason I replaced this entire assembly.