Originally Posted by canklecat

Yup, the master link needs to be on the top run of chain for the pedal to exert enough pressure to snap it shut.

Also be sure it's the right size Missing Link for the chain. KMC makes two sizes -- 7.1mm and 7.3mm -- very slightly different, but they aren't interchangeable. (Can't check other details right now because KMC's website appears to have been hijacked. Again. Probably a temporary thing over the Memorial Day holiday weekend. Seems like some unsecured websites get hijacked often by spammers and scammers.)

FWIW I just use pliers or heavy duty surgical clamps to open Missing Links at home. I carry a spare on the road but don't carry a tool. I figure if I need the replacement Missing Link the old one has already popped open and gotten lost, so I don't need the tool. But after a Missing Link has been reused a few times it opens fairly easily without a special tool. And the Missing Link seems to hang on pretty securely even when I drop the chain. So far I haven't lost one.

And I wax my chains so I can handle them on with bare hands. Very clean, very little mess -- about like pencil graphite. Boeshield T-9 is pretty clean too, just needs to be applied more often.