Master Lock Won't Open with Key


Well-Known Member
  • #1
I just tried opening my Master lock that I have locking my trailer up and it wouldn't open. It's been raining and snowing a lot lately, so I thought the internals had frozen again. I got my cigarette lighter out again and put a flame to the bottom of the lock. That didn't work. Then I went and grabbed my propane torch to heat the lock up. That didn't work either. This is the first time this lock had ever given me problems, besides being frozen shut. After I use the torch on it, it always opens right up. This time, nothing would work. I would turn the key and it just wouldn't turn.

I first thought that by heating the lock up so much with the torch that I had melted some plastic parts inside of it. Then I thought better of that. Who uses plastic parts inside a padlock? Then I thought that perhaps some of the parts inside had corroded because of all the moisture that seeps inside. I grabbed my hammer and gave the lock a few taps. Then I tried the key again and that turned easily and the lock sprang open. Problem solved. Some of the small interior parts must have been stuck. They just needed to be jostled a bit to loosen up.

After I opened the lock, I sprayed some WD-40 silicone lubricant into the keyhole and then down the open shaft of the lock. Actually, I sprayed it down both sides of the lock, so that should help from getting stuck in the future. This lock keeps my trailer secure and it remains outside, so I'd rather not have it get stuck from the weather. But that's just the way it's going to be. Hopefully the silicone lubricant will repel the rain and snow. I hope this helps someone who may be experiencing the same problem.


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Well-Known Member
  • #2
This has happened to me so many times in the past. I've used a lighter to heat up the keyhole on warmer days, but if it's too cold out, I grab my turbo torch and that takes care of the frozen interior parts quickly. Over time though, that moisture does corrode the interior mechanisms. A nice whack with a wrench or a hammer usually takes care of that problem. One time I waited too long though and one of my locks rusted. Nothing could open it. I had to grind that one off. I would have used bolt cutters, but the lock was too large and I didn't have cutter big enough. A grinder is perfect for a job like that. Sucks that I lost a lock though.