"beer will leak from the three holes on the tower where it tightens to the faucet"?
Are you talking about the holes you put the wrench in to tighten the faucet to the shank?
I had one 525 that leaked from this connection, it just needed tightened some more. I took it apart, made sure the oring wasn't messed up, lubed it good and put it back on a second time. Still leaked so I put the wrench on and tightened it slowly till it stopped leaking. Next time I take a faucet off, I will hook up an empty keg with air in it so I know it won't leak beer and make a mess.