Saginaw pump leak (with Borgeson bracket)

There are square o-ring between the can and the main pump body. The clamping from the bolt makes the seal.

It was 2011 when I least did this, so going by memory…. there are special bolts that have a hex on the center of them that gets tightened. Then the bracket slips over the threads that go past the hex. And a nuts tightens the bracket to the pump.