I have a mini U-lock from OnGuard.
The lock is not attached to the bike, so that's not a factor is this question.

I can see the locking mechanism jutting out partially into the key hole, which is preventing the key from being fully inserted into the key hole--it only can go about 1/2 in. How can I get the mechanism to go back in to place so that my key may be fully inserted? Or is it time to finally break down and get a whole new lock?

  • 1
    If this is a standard tumbler lock it's not unusual for individual tumbler pins to slide down into the keyway. Generally one can overcome this problem by simply wiggling the key as you insert it. Sometimes a shot of TriFlow Teflon lube helps (though don't use WD40 or other such lubes). Aug 31, 2015 at 2:01
  • Note that even with TriFlow you need to know what lube you lock uses, as locks are often lubricated with graphite powder and the combination of oil plus graphite is not a lubricant.
    – Móż
    Aug 31, 2015 at 2:56
  • @Mσᶎ - TriFlow isn't an oil, and is compatible with graphite. Sep 1, 2015 at 0:42
  • @DanielRHicks the TriFlow I'm used to is an oil with PTFE in it, and when you add it to graphite you get mud. Slippery but sticky mud. And OMG the TriFlow website is awful, all animated and delay screens because apparently it's more important that I get to see their logo than anything about their products. But they say "High-grade petroleum oils", which suggests it's oil to me.
    – Móż
    Sep 1, 2015 at 1:19
  • 2
    @Mσᶎ - The TriFlow I've always used is Teflon and a propellant. The propellant evaporates, leaving only the Teflon. Sep 1, 2015 at 1:48

2 Answers 2


You can rotate the key back and forth while you insert it, That should help realign the cylinders. This actually a common problem and doesn't mean that the lock is broken.

Take it to your bike shop if you continue to have problems. They are experts at the jiggle-dance sometimes necessary to get the key in.


If jiggling the key doesn't work, I found that jiggling something thinner, eg a toothpick or wire nail, works better because it can pass the rotated disks more easily. Push it in all the way and move it up and down.

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