turn the engine on but dont let it warm up because you will need to take that screw off , and wait till coolant starts shooting out...then you will have to cap it back on real fast.....

so follow these steps i guess

1) turn car on
2) take screw off
3) wait till coolant shoots out
4) put screw back on


stud problem i cant help you with...my stud broke inside my hub the other day with the lug still on it...what a day that was