make sure you rotate where you tap as well: go from 12 - 6 - 3 - 9 - and then you can go to the 45 spots. make sure the hard outer portion of the old seal is matched up with the harder outer portion of the new seal. as you can imagine, it is possible to have the hard corner of the old seal pierce the soft inner portion of the new seal. finally, make sure its seated evenly all around.