[blucar]

Do not tighten the external bolts prior to inserting the concealed bolt. Use a six point socket with a 3"-4" extension, use a small piece of paper torn from a shopping bag, hold the paper over the socket, press the bolt head into the socket, bolt is now locked into the socket without the use of glue, therefore it is easily removed.
Use anti-seize on the bolt threads. Don't over tighten, a short 3/8 ratchet is all the torque needed.